4 “Listen to Me, My people; And give ear to Me, O My nation: For law will proceed from Me, And I will make My justice rest As a light of the peoples. 5 My righteousness is near, My salvation has gone forth, And My arms will judge the peoples; The coastlands will wait upon Me, And on My arm they will trust. Isaiah 51:4–5 (NKJV) 

4 Listen to me, listen to me, my people, and you kings, give ear to me, because the law will go forth from me, and my judgment as a light to the nations. 5 My righteousness approaches quickly, and even my salvation will go forth as a light, and nations will hope in my strength. Islands will wait for me and will hope in my strength. Isaiah 51:4–5 (LES2) 

Once we understand that the Old Testament scriptures point to Christ rather than to a resurrection of old covenant Israel, our grasp of what they mean will increase. 

God’s people have always been those who relate to him by faith, going all the way back to Abraham and continuing into the New Covenant. (Galatians 3:9) Therefore, when God speaks to his people, he is speaking to those who are chosen in Christ before the foundation of the world. (Ephesians 1:4) The elect in Christ is a nation of kings and priests (1 Peter 2:9). God announces to his people that his justice or judgment will be a light to the nations. We know that refers to Christ, about whom it was said he would be a light to the Gentiles. (Acts 13:47)

The MT gets it wrong by emphasizing judgment instead of salvation. God’s judgment fell on Christ so that those who believe in him will be justified. Instead of the MT’s “My arms will judge the peoples,” the LXX says, “nations will hope in my strength.” The gospel has reached the nations bringing hope to the lost.

6 Lift up your eyes to the heavens, And look on the earth beneath. For the heavens will vanish away like smoke, The earth will grow old like a garment, And those who dwell in it will die in like manner; But My salvation will be forever, And My righteousness will not be abolished. Isaiah 51:6 (NKJV) 

6 Lift your eyes up to the heavens and look at the earth below, for the heavens will become solid like smoke, and the earth will grow old like a garment, and those who inhabit it will die just like these things, but my salvation will be for eternity, and my righteousness will certainly not come to an end. Isaiah 51:6 (LES2) 

7 “Listen to Me, you who know righteousness, You people in whose heart is My law: Do not fear the reproach of men, Nor be afraid of their insults. 8 For the moth will eat them up like a garment, And the worm will eat them like wool; But My righteousness will be forever, And My salvation from generation to generation.” Isaiah 51:7–8 (NKJV) 

7 Listen to me, you who know judgment, people of whom my law is in your heart. Do not fear the reproach of humans, and do not be overcome by their contempt. 8 For like a garment it will be eaten up by time, and like wool it will be eaten up by a moth; but my righteousness will be for eternity, and my salvation for generations of generations. Isaiah 51:7–8 (LES2) 

Once again, it is important to discern to whom this passage is addressed. The key is the phrase, “people of whom my law is in your heart.” This can only mean New Covenant believers, about which Jeremiah wrote:

33 “For this is my covenant that I will establish with the house of Israel after those days,” declares the Lord. “In giving, I will give my laws into their mind, and I will write them upon their hearts. And I will become a God for them, and they will become a people for me. Jeremiah 38:33 (LES2) 

To us, God warns and encourages us not to fear reproach and contempt that will come our way from those whose hearts are closed to the gospel. Death will put an end to our persecutors, but God’s salvation never ends.

9 Awake, awake, put on strength, O arm of the LORD! Awake as in the ancient days, In the generations of old. Are You not the arm that cut Rahab apart, And wounded the serpent? 10 Are You not the One who dried up the sea, The waters of the great deep; That made the depths of the sea a road For the redeemed to cross over? 11 So the ransomed of the LORD shall return, And come to Zion with singing, With everlasting joy on their heads. They shall obtain joy and gladness; Sorrow and sighing shall flee away. Isaiah 51:9–11 (NKJV) 

9 Awake, awake, Jerusalem, and put on the strength of your arm! Awake as at the start of the day, as the eternal generation. Are you not 10 the one who laid the sea waste, the abundant water of the abyss? Are you not the one who put a way of passage at the bottom of the sea for those who are rescued 11 and for those who are ransomed? For they will be returned by the Lord, and they will come to Zion with cheer and eternal rejoicing, for praise will be upon their head, and cheer will seize them; grief and sorrow and sighing have fled. Isaiah 51:9–11 (LES2) 

Here Jerusalem is called to put on the strength of her arm, which is Christ, who is identified in Isaiah 53 as the “arm of the Lord.”

1 O Lord, who has believed our report? And to whom has the arm of the Lord been revealed? Isaiah 53:1 (LES2) 

The exhortation is to awaken through the new birth, by which believers become part of the “eternal generation,” the new edition of mankind that the Holy Spirit engenders via the new birth – the day that started when Christ rose from the dead, the day of the Lord.

The Israel of God, the church, the one new man in Christ, is this eternal generation, who will be filled with joy because of God’s mercy and love poured out on us.

3 And I heard a loud voice from heaven saying, “Behold, the tabernacle of God is with men, and He will dwell with them, and they shall be His people. God Himself will be with them and be their God. 4 And God will wipe away every tear from their eyes; there shall be no more death, nor sorrow, nor crying. There shall be no more pain, for the former things have passed away.” 5 Then He who sat on the throne said, “Behold, I make all things new.” And He said to me, “Write, for these words are true and faithful.” Revelation 21:3–5 (NKJV)