And they sung a new song, saying, Thou … hast redeemed us to God by Thy blood, out of every kindred, and tongue, and people, and nation … – Revelation 5:8

…the Lord hath done it… – Isaiah 44:23

Sinner, though you have not this redemption, yet I would have you sing about it, for it is precisely what you want. You are slaves to sin, and ought you not to bless God that there can be such a thing as redemption? …Many are redeemed, and are rejoicing in it; why should it not come to you? At any rate, begin to hope.

Rejoice, because salvation is a work done for you by another hand. “The Lord hath done it.” A redemption in which you had to find a part of the price would not make you sing, for you are too poor to contribute a farthing, but the Lord has found the whole cost to the utmost penny. If ever you are saved, it must be by power beyond your own, for you are weak as water; be glad, then, that the Lord has done it. If you can ever get that thought into your mind (and I pray the Holy Ghost to put it there), that your salvation was completed on the tree by the Lord Jesus, why, methinks, you will with joy shout forth the Redeemer’s praise.

Think again “the Lord hath done it,” even He whom you have offended. The God whom you have grieved has condescended to work out your redemption. Ought not this to make your soul say, “Would God it were for me”? and then begin to sing even at the bare possibility of such a thing. “Only trust Him now! He will save you. He will save you. He will save you now.” ~ C.H. Spurgeon

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