Isaiah 63:7

The prophet is here, in the name of the church, taking a review, and making a thankful recognition, of God's dealings with his church all along, ever since he founded it, before he comes, in the latter end of this chapter and in the next, as a watchman upon the walls, earnestly to pray to God for his compassion towards her in her present deplorable state; and it was usual for God's people, in their prayers, thus to look back. I. Here is a general acknowledgment of God's goodness to them all along, Isa 63:7. It was said, in general, of God's prophets and people (Isa 62:6) that they made mention of the Lord; now here we are told what it is in God that they do especially delight to make mention of, and that is his goodness, which the prophet here so makes mention of as if he thought he could never say enough of it. He mentions the kindness of God (which never appeared so evident, so eminent, as in his love to mankind in sending his Son to save us, Tit 3:4), his loving-kindness, kindness that shows itself in every thing that is endearing; nay, so plenteous are the springs, and so various the streams, of divine mercy, that he speaks of it in the plural number - his loving-kindnesses; for, if we would count the fruits of his loving-kindness, they are more in number than the sand.

— Matthew Henry's Concise Commentary (public domain)

Israel's penitential confession and prayer for restoration (Psa 102:17, Psa 102:20), extending from Isa. 63:7-64:12. loving-kindnesses . . . praises . . . mercies . . . loving-kindnesses--The plurals and the repetitions imply that language is inadequate to express the full extent of God's goodness. us--the dispersed Jews at the time just preceding their final restoration. house of Israel--of all ages; God was good not merely to the Jews now dispersed, but to Israel in every age of its history.

— Jamieson-Fausset-Brown Commentary (public domain)