Isaiah 59:21 — “And as for me, this is my covenant with them,” says the Lord: “My Spirit that is upon you, and my words that I have put in your mouth, shall not depart out of your mouth, or out of the mouth of your offspring, or out of the mouth of your children’s offspring,” says the Lord, “from this time forth and forevermore.”
Commentary by Albert Barnes
As for me – In the previous part of the chapter, the prophet has spoken. Here Yahweh is introduced as speaking himself, and as declaring the nature of the covenant which he would establish. In the verse previous, it had been stated that the qualifications on the part of people for their partaking of the benefits of the Redeemer‘s work, were, that they should turn from transgression. In this verse, Yahweh states what he would do in regard to the covenant which was to be established with his people. ‹So far as I am concerned, I will enter into a covenant with them and with their children.‘
This is my covenant with them – (Compare the notes at Isaiah 42:6; Isaiah 49:8; Isaiah 54:10). The covenant here referred to, is that made with people under the Messiah. In important respects it differed from that made with the Jewish people under Moses.
The word, ‹covenant‘ here is evidently equivalent, as it is commonly, when applied to When it is said, ‹this is my covenant,‘ the import evidently is, ‹this is the nature or the tenure of my covenant, or of my solemn promises to my people under the Messiah. It shall certainly occur that my Spirit will be continually imparted to thy seed, and that my words will abide with thee and them forever.‘
My Spirit that is upon thee – The word ‹thee‘ here does not refer, as Jerome and others suppose, to the prophet, but to the pious Hebrew people. The covenant under the Messiah, was not made especially with the prophet or his posterity, but is a promise made to the church, and here evidently refers to the true people of God: and the idea is, that the Spirit of God would be continually imparted to his people, and to their descendants forever. It is a covenant made with true believers and with their children.
And my words – The Chaldee understands this of prophecy. But it seems rather to refer to the truth of God in general which he had revealed for the guidance and instruction of his church.
Shall not depart out of thy mouth – This phrase probably means, that the truth of God would be the subject of perpetual meditation and conversation. The covenant would be deemed so precious that it would constantly dwell on the tongues of those who were interested in it.
Thy seed‘s seed – Thy descendants; thy posterity.
From henceforth and for ever – This is in accordance with the promises which everywhere occur in the Scriptures, that God would bless the posterity of his people, and that the children of the pious should partake of his favor.
See Exodus 20:6: ‹Showing mercy unto thousands (that is, thousands of generations) of them that love me and keep my commandments.‘ Compare Deuteronomy 4:37; Deuteronomy 5:29; Deuteronomy 7:9; Psalm 89:24, Psalm 89:36; Jeremiah 32:39-40.
There is no promise of the Bible that is more full of consolation to the pious, or that has been more strikingly fulfilled than this. And though it is true that not all the children of holy parents become truly pious; though there are instances where they are signally wicked and abandoned, yet it is also true that rich spiritual blessings are imparted to the posterity of those who serve God and who keep his commandments.