1 Samuel 15:29

29. Strength of Israel Jehovah, thus called not only because of his omnipotence, but also because of his constancy and truth the glorious object of Israel’s confidence.

Will not lie nor repent Compare 1 Samuel 15:11 and note there. Jehovah has feelings of love and anger: love for the righteous and anger towards the wicked. If the righteous man turn from his righteousness, or the wicked from his wickedness, towards him correspondingly Jehovah’s feelings change. This is often called repentance in God. But beyond this the divine Nature is not subject to change. In man, however, repentance implies sinfulness and fallibility, and involves a moral and religious change, so that it is never after the manner of man that God repents.