And they sang a new song:  "You are worthy to take the scroll and to open its seals, because you were slain, and with your blood you purchased men for God from every tribe and language and people and nation. [10] You have made them to be a kingdom and priests to serve our God, and they will reign on the earth." (Rev. 5:9-10, NIV).
In past lessons we have seen a different viewpoint of the Lamb of God. The focal point of  God's Lamb is the finished work that He did on the cross.  We cannot dare diminish that point a bit.  But Revelation has shown the other side of the "coin" as it were.  I take as the capstone passage of the Lamb of God Revelation 5:5 & 6 where both the imagery of the Lion of Judah and the Lamb appear.  We must not look at the events leading up the cross alone when it comes to Jesus, the Lamb of God.  Redemption's plan pivots on Jesus' willingness and ability to be the executor of it.
First of all we have the reign of Jesus Christ as the direct descendent of David, Judah and thence Abraham – this is Jesus the Lion of Judah.  Permit me some time to journey through the Bible and look at some passages that point to Jesus as the Lion – particularly the Lion of  Judah.
A Brief Journey – Jesus the Lion of Judah.
"Judah, your brothers will praise you;  your hand will be on the neck of your enemies;  your father's sons will bow down to you. [9] You are a lion's cub, O Judah; you return from the prey, my son. Like a lion he crouches and lies down, like a lioness--who dares to rouse him?  [10] The scepter will not depart from Judah, nor the ruler's staff from between his feet, until he comes to whom it belongs and the obedience of the nations is his."   Genesis 49:8-10, NIV.
Here is the first reference to the Lion.  Judah was to be the bloodline through which Jesus Christ would come.  The promise is clear!  God promises Judah that he will be the head of the family in the long run that his brothers who will make up the other tribes of Israel will recognize his  headship. It is from appellation of Judah that we get the name of the present race, Jew.  When the kingdom of Israel was divided, it was Judah that was last to fall to the divine judgment of God.
"A maskil of Ethan the Ezrahite.  I will sing of the LORD'S great love forever;  with my mouth I will make your faithfulness known through all generations.  [2] I will declare that your love stands firm forever, that you established your faithfulness in heaven itself.  [3] You said, "I have made a covenant with my chosen one, I have sworn to David my servant,  [4] 'I will establish your line forever and make your throne firm through all generations.' "   Selah Psalm 89:1-4, NIV.
God is a God of faithfulness and love.  It is based on the character of God that we see here David's line through which God will establish in perpetuity His reign.  The key here is that God not only promises that David's Son will reign but that He will reign on earth.  This is the Lion of Judah – the animal of nobility – the lion is to become this image of the noble reign of Jesus Christ as the Lion of Judah.
God places His Sovereignty in the Hand of The Descendent of Judah.
Gilead is mine, and Manasseh is mine; Ephraim is my helmet, Judah my scepter. Psalm 60:7, NIV.
That God will reign on earth is not a debatable question.  The point of Psalm 60:7 and also 108:8 is that Judah will be His scepter!  This is a direct reference to Jesus Christ.  God will possess the tribes of Israel – further than this – God will rule on earth through Jesus Christ, a direct descendent of Judah.
In that day the Root of Jesse will stand as a banner for the peoples; the nations will rally to him, and his place of rest will be glorious.  [11] In that day the Lord will reach out his hand a second time to reclaim the remnant that is left of his people from Assyria, from Lower Egypt, from Upper Egypt, from Cush, from Elam, from Babylonia, from Hamath and from the islands of the sea. [12] He will raise a banner for the nations and gather the exiles of Israel; he will assemble the scattered people of Judah from the four quarters of the earth. Isaiah 11:10-12
Jesus the Root. Curious reference to Jesus Christ the grandson many times removed from David's father – Jesus Christ is the root.  Some Bible expositors try to make this to mean that a shoot will come out the line of Jesse.  This is not the meaning from the original.  This means that everything that the Davidic line stands for – indeed the very significance of the Davidic line is based on the very person of Jesus Christ.  Without Jesus Christ the Davidic line would just be another dynasty that appeared and then disappeared from the pages of time.  It is the root of Jesse that will reach out and reclaim His people.  The islands of the sea may very well refer to the yet to be discovered continents – not merely some small islands yet unnamed.  
Jesus the Banner.  Then we see the reference to Jesus Christ to "a  banner."  The same word is used in connection with God in Exodus 17:15; "Moses built an altar and called it The LORD is my Banner." This reference in Isaiah 11 may be a veiled reference to the divinity of Jesus Christ, say some Bible expositors.  There are other references to this word; for example in Isaiah 62:10-63:6  - here Jesus Christ is the victor over his enemies.  It is the banner that is raised to celebrate the victory.
So then, the Banner that the Root, Jesus Christ, will raise, will be the Banner of victory, Jesus Christ Himself,  over Satan's domain – He will be sovereign as the Banner of God. This is Jesus Christ the Lion and the Lamb. 
The Victory of The Lamb of God.
The Victory of the Lamb Illustrated by Roman Law.
But thanks be to God, who always leads us in triumphal procession in Christ and through us spreads everywhere the fragrance of the knowledge of him.  [15] For we are to God the aroma of Christ among those who are being saved and those who are perishing.  [16] To the one we are the smell of death; to the other, the fragrance of life. And who is equal to such a task? 2 Cor. 2:14-16, NIV.
Victory is assured.  Paul refers  to Christ's victory in the Roman practice of the returning victorious Roman Generals who would, in their return, be granted a grand procession  through the city where the way would be lined with garlands of flowers.   Vessels of incense would be carried in advance of the procession.  Thus the fragrance of the flowers and the burning incense would be a reminder that a victory procession was in progress.  Here Paul was encouraging his friends that they would be in that Grand Procession with Christ as the Victor.
When you were dead in your sins and in the uncircumcision of your sinful nature, God made you alive with Christ. He forgave us all our sins,  [14] having canceled the written code, with its regulations, that was against us and that stood opposed to us; he took it away, nailing it to the cross.  [15] And having disarmed the powers and authorities, he made a public spectacle of them, triumphing over them by the cross. Col. 2:13-15, NIV.
Oh, this is so rich in detail.  In our previous picture, Christ was the victorious general, Paul and his co-workers were the soldiers of the cross (from this imagery, many of whom were former captives but now Roman soldiers), the captives who were to live were those who had come to Christ because of Paul's and his friends' evangelistic work, these captives were to live because of royal decree.  Some of the condemned were to die because of their former political position – this would be a picture of Satan and his henchmen along with those who had refused the Gospel.  So the fragrance to some of the captives meant life – these were the captives who were to be released in the Roman form of slavery that meant a new life – of service to the Roman empire.  Now we look at some more detail – the condemnation of the Emperor stood out in absolute result – condemnation against the captives.  We as sinners were condemned to death – the death of eternal punishment.  This decree stood out against us:
What then? Are we better than they? Not at all; for we have already charged that both Jews and Greeks are all under sin;  [10] as it is written,        "THERE IS NONE RIGHTEOUS, NOT EVEN ONE;          [11] THERE IS NONE WHO UNDERSTANDS,        THERE IS NONE WHO SEEKS FOR GOD;          [12] ALL HAVE TURNED ASIDE, TOGETHER THEY HAVE BECOME USELESS;        THERE IS NONE WHO DOES GOOD,        THERE IS NOT EVEN ONE."          [13] "THEIR THROAT IS AN OPEN GRAVE,        WITH THEIR TONGUES THEY KEEP DECEIVING,"         "THE POISON OF ASPS IS UNDER THEIR LIPS";          [14] "WHOSE MOUTH IS FULL OF CURSING AND BITTERNESS";          [15] "THEIR FEET ARE SWIFT TO SHED BLOOD,          [16] DESTRUCTION AND MISERY ARE IN THEIR PATHS,          [17] AND THE PATH OF PEACE HAVE THEY NOT KNOWN."          [18] "THERE IS NO FEAR OF GOD BEFORE THEIR EYES." Romans 3:9-18, NAS.  This is the decree against us all.  Further on in Paul's reading of God indictment against us all was that every man has fallen short of the glory of God – in chapter 6 of Romans Paul pounds the last nail in every sinners "casket" that the wages of sin is death!  So then, this is the document of condemnation that is read before every man and woman.  But here the imagery of Colossians comes to life – The Lamb of God stepped in took the decree of condemnation and nailed to the cross.  The "powers and authorities" are Satan and his henchmen. He thought he had thwarted God's plan of redemption of man – they are made a public spectacle in this Roman imagery and put to death before all by being cast into the lake of fire – an eternity of punishment that was designed only for the fallen angels.
The Victory of Jesus Christ, the Lamb of God
As depicted in Revelation.
"And they sang a new song, saying, "Worthy art Thou to take the book, and to break its seals; for Thou wast slain, and didst purchase for God with Thy blood men from every tribe and tongue and people and nation.  [10] "And Thou hast made them to be a kingdom and priests to our God; and they will reign upon the earth." Rev. 5:9-10, NAS
What a choir!  What a wonderful time there will be in heaven when this new song is sung.  The book of seals contains seven seals.  While it is not the purpose of this lesson to treat in detail the events of the Great Tribulation it is important from the point of view that only the Lamb of God was worthy to open this book of seals.  The seals within this book refer to the practice in biblical times of making a will or decree authentic and to carry out that decree upon the death of the testator.  The seal was made by the Father in behalf of His Son.  Only Jesus, the Lamb of God who was dead and is now alive can open these seals and thus carry out the decree of The Father.  The period of the Tribulation has been described as God's judgment of the unbelieving nations – more correctly – it is God's final assertion of His sovereignty over the earth and in the process it is the Lamb's final execution of the Father's decree.  Thus the opening of seals.  Six of the seals deal with the final judgment of God on Satan's world system and the Lamb's usurping of that system. The seventh seal is the carrying out of the guarantee that there would be men from every tribe and tongue and people and nation who would be called out of Satan's kingdom and become "…a kingdom and priests to our God; and they will reign upon the earth…"
This victory is described in Revelation as the ultimate redemption from and wresting of "ownership" of countless men "from every tribe and tongue and people and nation" from Satan's rule. Note that it is the Lamb who opens the seals of this Book – this final last will and testament of the Lamb.
The Carrying out of the Father's will.
Then I looked, and there before me was the Lamb, standing on Mount Zion, and with him 144,000 who had his name and his Father's name written on their foreheads.  [2] And I heard a sound from heaven like the roar of rushing waters and like a loud peal of thunder. The sound I heard was like that of harpists playing their harps.  [3] And they sang a new song before the throne and before the four living creatures and the elders. No one could learn the song except the 144,000 who had been redeemed from the earth.  [4] These are those who did not defile themselves with women, for they kept themselves pure. They follow the Lamb wherever he goes. They were purchased from among men and offered as firstfruits to God and the Lamb. Rev. 14:1-4, NIV.
144,000 virgin men from every tribe of Israel will be sealed (as a mark of ownership and as a mark of the carrying out of the Father's will).  They will become believers in the Lamb of God – in Jesus Christ and will be the means of the final evangelism of the entire world.  These evangelists will be lead by the Lamb in a victorious world-wide proclamation of the Gospel and thus the Father's desire will be carried out.
And I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glass, having the harps of God.  [3] And they sing the song of Moses the servant of God, and the song of the Lamb, saying, Great and marvellous are thy works, Lord God Almighty; just and true are thy ways, thou King of saints. Rev. 15:2-3, KJV.
The battle is brought to the finish – it is the Lamb who is the victor.  The final phrase is so true – He is the King of saints.