21. Remember these things, O Jacob. He now applies to the use of the people what he had so often said about the superstitions and falsehoods of the Gentiles, by which men who are not well instructed are deceived in the worship of God. Nor does he write these things solely for the men of his own age, but chiefly for their posterity, who were to be carried away into Babylon, and might have been corrupted by long intercourse with the Babylonians, and drawn aside from the true worship of God, if the Lord had not laid upon them those restraints. The Prophet therefore exhorts them, while they were held captive, to bring those exhortations to remembrance, and by means of them to strengthen their hearts amidst those grievous calamities.
For thou art my servant, I have formed thee. He adds this reason why they ought to remember these promises, and to beware of the general contagion of other men; for it would have been intolerable that the elect people, whom God had surrounded by the barriers of his Law, that they might be separated from others, should freely and indiscriminately mingle with the pollutions of the Gentiles. As if he had said, “It is not wonderful that the Babylonians should wander in their errors, but thou oughtest to be unlike them; for ‘I have formed thee,’ that thou mightest ‘serve me;’ I have regenerated and sanctified thee, that thou mightest be an heir of eternal life.”
Of this creation we have stated largely, on former occasions, that it relates to the renewal of the soul. Scripture frequently employs this argument, “Ye have been called to sanctification and not to uncleanness,” (1 Thess. 4:7,) “Walk as the children of light” (Eph. 5:8) “in the midst of a crooked and perverse nation,” (Philip. 2:15,) and in other passages of the same kind. Here we ought to infer that we shall be doubly punished, if it shall be found that we have quenched by neglect or indifference the light by which the Lord hath enlightened us; for our criminality will be far greater than that of others on whom he has not bestowed a similar favour. Heathens shall indeed be punished, and no excuse of ignorance shall be of any avail to them; but far heavier shall be the punishment of those who shall abuse the grace of God.
Do not thou forget me. He means that it is impossible for any who have once entered into the right path to be led aside from it, if they are not chargeable with forgetfulness of God; for error and delusions can never prevail, so long as the remembrance of God is rooted in our hearts. Let every one, therefore, who turns aside from God, and falls into superstition and impiety, lay the blame on his own wickedness. We ought thus to observe carefully the cause of apostasy, that is, forgetfulness of God, which gradually withdraws us from the right path, till we leave it altogether. Besides, he reminds them that by this remedy they will be secure against revolt, if they be employed in constant meditation; for our minds, through their sluggishness, easily contract rust, so to speak, which infects and corrupts all knowledge of God till it be entirely destroyed.
21 Here the prophet draws on one of the great themes of Deuteronomy: Remember (cf. Deut. 8:2, 11, 18; 9:7). There it signifies the recollection of what God has done in the history of Israel that ought to motivate the people to obedient living. Here, depending to some extent on the precise meaning assigned to “these things,” it is not so much the specific acts of God that are to be remembered as certain concepts about him. Nevertheless, the sense is the same: life is to be lived on the basis of reflection on the character of God as revealed in his treatment of his people in their historical experience. Reflection on the great natural cycles or on recurring psychological or sociological characteristics of humanity is not the foundation on which either the Hebrew or the Christian religion is based.
Scholars do not agree as to the precise referent of these things that are to be remembered. The first question is whether the reference is to what precedes in the text or to what follows. Commentators are fairly evenly divided, and a good case can be made for either. On the one hand, “remember” most naturally calls to mind what has already been said, unless there is a specific marker to the contrary (e.g., “I want you to remember what I am going to tell you next”). Furthermore, vv. 21 and 22 seem to form the conclusion to the unit that began at 42:10 and that focused on the evidence that God, not the idols, could redeem his people. Thus the point would be that Israel should remember all the evidence that no idol could possibly keep God from delivering them.
Ranged against this position are such commentators as Pieper and Elliger, both of whom believe that the reference is to what follows, namely, that Israel was formed by God to be his servant and that he has swept away their sins out of pure grace. The chief argument against this otherwise attractive position is that the verses almost certainly now function as a conclusion, at least to 44:6–20, if not to 42:10–44:20. That is, it is hard to see the call to remember focusing on just the following clauses, when all the great assertions concerning God’s nature and character vis-à-vis the gods have preceded.
All of Israel’s remembering is to be in the context of her special relationship to God. He had not merely shaped her, but he had shaped her for the special purpose of service. The role of servanthood is mentioned twice in three phrases, and the second occurrence is emphatic. Thus in the light of all that has been said about the Lord’s superiority over the idols and in the light of this special relationship that Israel bears to him, she must not interpret the exilic experience to mean that God has forgotten her. The purpose for which he created her—evidence of his sole Godhood—has not yet been fulfilled. How can he cast her off?
21. Remember—“Be not like the idolaters who consider not in their heart” (Is 44:19).
these—things just said as to the folly of idol-worship.
my servant—not like the idolaters, slaves to the stock of a tree (Is 44:19). See Is 44:1, 2.
thou … not … forgotten of me—Therefore thou oughtest to “remember” Me.
Ver. 21.—Remember these; rather, remember these things: i.e. the futility of idols and the folly of the idol-worshippers. For thou art my servant. Therefore bound to worship me, and not the idols (comp. ch. 41:8; vers. 1, 2). I have formed thee (so also in ch. 43:1, 21; vers. 2, 24). The duty of absolute unquestioning obedience seems contained in the relation of that which is formed to that which has formed it. On the other hand, it may be assumed that he who has formed a thing will have a constant care of it and regard for it—that at any rate he will not “forget” it.
 Jamieson, R., Fausset, A. R., & Brown, D. (1997). Commentary Critical and Explanatory on the Whole Bible (Vol. 1, p. 481). Oak Harbor, WA: Logos Research Systems, Inc.