Sforno on Exodus 6:4/ספורנו על שמות ו׳:ד׳

1וגם הקימותי, I have also sworn, as per Onkelos in Genesis 31,53 on the word וישבע which he renders as וקיים. “G’d swore to keep His promise.” Compare a similar phrase but worded differently in Psalms 106, 44-45. “When He saw that they were in distress, when He heard their cry, He was mindful of His covenant and in His great faithfulness He relented.”