Repenting means revising one's judgment and changing one's plan of action. God never does this; he never needs to, for his plans are made on the basis of a complete knowledge and control which extends to all things past, present, and future, so that there can be no sudden emergencies or unlooked-for developments to take him by surprise. "The counsel of the Lord stands for ever, the thoughts of his heart to all generations" (Ps. 33:11). What he does in time, he planned from eternity. And all that he planned in eternity, he carries out in time. And all that he has in his Word committed himself to do, will infallibly be done. Thus we read of the "unchangeable character of his purpose" to bring believers into full enjoyment of their promised inheritance, and of the immutable oath by which he confirmed his counsel to Abraham, the archetypal believer, both for Abraham's own assurance and also for others (Heb. 6:17-19). So it is with all God's announced intentions. They do not change. No part of his eternal plan changes.
It is true that there is a group of texts (Gen. 6:6-8; 1 Sam. 15:11; 2 Sam. 24:16; Joel 2:13-14; Jon. 3:10) which speak of God as repenting. The reference in each case is to a reversal of God's previous treatment of particular men, consequent upon their reaction to that treatment. But there is no suggestion that this reaction was not foreseen, or that it took God by surprise, and was not provided for in his eternal plan. No change in his eternal purpose is implied when he begins to deal with a person in a new way.