Deuteronomy 29:4

The Lord hath not given you a heart, etc. - Some critics read this verse interrogatively: And hath not God given you a heart, etc.? because they suppose that God could not reprehend them for the non-performance of a duty, when he had neither given them a mind to perceive the obligation of it, nor strength to perform it, had that obligation been known. Though this is strictly just, yet there is no need for the interrogation, as the words only imply that they had not such a heart, etc., not because God had not given them all the means of knowledge, and helps of his grace and Spirit, which were necessary; but they had not made a faithful use of their advantages, and therefore they had not that wise, loving, and obedient heart which they otherwise might have had. If they had had such a heart, it would have been God's gift, for he is the author of all good; and that they had not such a heart was a proof that they had grieved his Spirit, and abused the grace which he had afforded them to produce that gracious change, the want of which is here deplored. Hence God himself is represented as grieved because they were unchanged and disobedient: "O that there were such a heart in them, that they would fear me, and keep all my commandments always, that it might be well with them and with their children for ever!" See Deuteronomy 5:29 (note), and the note there.

Ability to understand the things of God is the gift of God (compare 1 Corinthians 2:13-14); yet man is not guiltless if he lacks that ability. The people had it not because they had not felt their want of it, nor asked for it. Compare 2 Corinthians 3:14-15.

29:4 Yet the Lord - That is, you have perceived and seen them with the eyes of your body, but not with your minds and hearts; you have not yet learned rightly to understand the word and works of God, so as to know them for your good, and to make a right use of them, and to comply with them: which he expresseth thus, the Lord hath not given you, &c. not to excuse their wickedness, but to direct them to whom they must have recourse for a good understanding of God's works; and to intimate that although the hearing ear, and the seeing eye, be the workmanship of God, yet their want of his grace was their own fault, and the just punishment of their former sins; their present case being like theirs in Isaiah's time, who first shut their own eyes and ears that they might not see and hear, and would not understand, and then by the righteous judgment of God, had their eyes and ears closed that they should not see and hear, and understand. God's readiness to do us good in other things, is a plain evidence, that if we have not grace, that best of gifts, 'tis our own fault and not his: he would have gathered us, and we would not.