Charles H. Spurgeon on Psalms 103:9

(Second Clause). To keep anger for ever, corresponds with the French phrase, Je lui garde, Il me la garde, (*"I am watching him, as he has watched to do a bad turn to me") which we use when the man, who cannot forgive the injuries he has received, cherishes secret revenge in his heart, and waits for an opportunity of retaliation. Now David denies that God, after the manner of men, keeps anger on account of injuries done to him, since he condescends to be reconciled. Calvin.