I will mention - This is evidently the language of the people celebrating the praises of God in view of all his mercies in former days. See the analysis to the chapter. The design of what follows, to the close of Isaiah 64:1-12, is to implore the mercy of God in view of their depressed and ruined condition. They are represented as suffering under the infliction of long and continued ills; as cast out and driven to a distant land; as deprived of their former privileges, and as having been long subjected to great evils. Their temple is destroyed; their city desolate; and their whole nation afflicted and oppressed. The time is probably near the close of the captivity; though Lowth supposes that it refers to the Jews as scattered over all lands, and driven away from the country of their fathers. They begin their petitions in this verse with acknowledging God’s great mercies to their fathers and to their nation; then they confess their own disobedience, and supplicate, by various arguments, the divine mercy and favor. The Chaldee commences the verse thus, ‘The prophet said, I will remember the mercy of the Lord.’ But it is the language of the people, not that of the prophet. The word rendered ‘mention’ (אזכיר 'azekiyr), means properly, I will cause to remember, or to be remembered (see the notes at Isaiah 62:6).
And the praises of the Lord - That is, I will recount the deeds which show that he is worthy of thanksgiving. The repetitions in this verse are designed to be emphatic; and the meaning of the whole is, that Yahweh had given them abundant cause of praise, notwithstanding the evils which they endured.