Reply: Scripture speaks of God's repentance figuratively; it signifies an effect, not a feeling (1 Samuel 15)
The answer is that Scripture often ascribes human limbs and feelings to God by a figure of speech, not because they belong to him literally and properly. Much that is said of God in human terms (anthropopathos) must therefore be understood in a way fitting for God (theoprepos), in a manner worthy of him.
So when Scripture says that God repented, there is no more need to take this literally than what we read elsewhere, that God's heart was stirred or that smoke rose from his nostrils. Indeed, when Scripture speaks of repentance in the proper sense, it expressly denies it of God, as when Samuel says to Saul: 'The Glory, or Strength, of Israel will not lie or change his mind, for he is not a man, that he should repent' (1 Samuel 15).
In God, then, repentance means not a feeling but an effect. When Scripture says God repented, it puts the antecedent for the consequent: it means that God did what a man does who regrets something he has made. God resolved to wipe from the earth, because of their wickedness, the human beings he had made, as a man destroys a work he regrets.
Latin
XIII. Verum ad ista dicendum est, scripturam saepe Deo tribuere hominum membra & affectus tropice atque figurate, non autem quod ad litteram & proprie ipsi conveniant: ac proinde multa quae de Deo dicuntur ἀνθρωποπαθῶς, intelligenda esse θεοπρεπῶς, & modo qui Deo dignus sit. Itaque quum scriptura dicit, Deum fuisse poenitentia ductum, nihilo magis necesse est ut istud proprie sumamus, quam quod alibi legitur viscera Dei commota fuisse, & in nares ejus ascendisse fumum. Imo quum poenitentiam scriptura proprie sumit, expresse illam a Deo removet. Ut quum Samuel dicit ad Saulem, Triumphator, sive fortitudo, Israelis non mentietur, & poenitudine non flectetur: neque enim homo est ut agat poenitentiam, 1 Sam. 15. Poenitentia igitur in Deo significat non affectum, sed effectum. Ac quum ait scriptura Deum poenituisse, antecedens pro consequente sumit, & significat Deum illud fecisse, quod faceret homo quem poenitet operis a se facti: nempe statuisse Deum homines a se factos, de terra, propter ipsorum iniquitatem delere; sicut homo destruit opus cujus ipsum poenitet.