Sing, O ye heavens; for the LORD hath done it…for the LORD hath redeemed Jacob and glorified Himself in Israel. – Isaiah 44:23

We may lay peculiar force upon the word, “The Lord hath done it,” for He has finished the work. In the matter of the redemption of His people nothing remains to be done. There is no mortgage on the church of God to be ultimately discharged, the Lord has made us His unencumbered freehold, and we are His own portion for ever. There is not a little left of human merit for the sinner to work out for himself, or some little point in which the work of salvation is incomplete; but “The Lord hath done it.” No, brethren, even the fringe of the robe of righteousness is all there; you have not a thread to add to it, it is without seam, and woven from the top throughout, all of one piece. Consummatum est. “It is finished;” every type fulfilled, every commandment kept, every sin abolished, the wrath of God and everything that hindered put away.

A very important part of the song, however, lies in the fact that what God has done glorifies Himself. Infinite mercy and condescending love reflect glory upon God…In redemption you see all the attributes of God, blended in harmony, shining with benignant radiance, not with the flash and flame of Sinai, but with the soft beams of peace and love from Calvary. God is never so gloriously seen as at the cross; no, not even amidst the flaming seraphim do the saints above enjoy such a view of God as when they see Him in the wounds of Jesus and putting their finger into the print of the nails, exclaim with transport, “My Lord and my God.” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1240.cfm