John Gill Commentary Isaiah 43:1

"But now thus saith Jehovah that created thee, O Jacob, and he that formed thee, O Israel: Fear not, for I have redeemed thee; I have called thee by thy name, thou art mine." — Isaiah 43:1 (ASV)

But now thus says the Lord that created you, O Jacob
This prophecy is not concerning Cyrus, and the redemption of the Jews by him, as some have thought; nor of Sennacherib and his army, and of their deliverance from him, as Kimchi and his father interpret it; but of the Christian church, and the state of it, when Jerusalem should be destroyed, as predicted in the preceding chapter; which goes by the name of Jacob and Israel, for the first churches chiefly consisted of Jews, and both Jews and Gentiles converted are the spiritual Israel of God.

and he that formed you, O Israel ;
this creation and formation are not so much to be understood of their being the creatures of God, and the work of his hands, in a natural sense; but of their new creation and regeneration; of their being the spiritual workmanship of God, created in Christ, and formed for his glory.

fear not: for I have redeemed you :
though Jerusalem shall be destroyed, and Judea wasted, and though subject to the persecutions of wicked men in all places; yet since redeemed by Christ from sin, Satan, and the law, hell, and death, nothing is to be feared from either of them; redemption by Christ is an antidote against the fear of any enemy whatsoever.

I have called you by your name ;
with an effectual calling, which is of particular persons, and those by name, even the same that are redeemed by Christ; for whom he has redeemed by his precious blood, they are called by the grace of God to special blessings of grace, with a high, holy, and heavenly calling; and have no reason to fear anything, since they are the chosen of God; have a right to all spiritual blessings; all things work together for their good; they shall persevere to the end, and at last be brought to glory, to which they are called.

you are mine ;
such as are redeemed by Christ, and called by his grace, they are his Father's gift, and his own purchase; they voluntarily give up themselves to him, under the influence of his Spirit and grace; they are his by profession and possession; they are his portion, people, sheep, and spouse; and his interest in them, and theirs in him, serve to prevent fear; such need not fear wanting anything, nor any enemy, nor perishing, or miscarrying of heaven and happiness, to which fears they are subject.