I will lengthen thy days - The promise here was only conditional. As the condition was not observed 1 Kings 11:1-8, the right to the promise was forfeited, and it was not fulfilled. Solomon can scarcely have been more than fifty-nine or sixty at his death.
Related Commentaries of 1 Kings 3:14
1 Kings 3:14
14 And if thou wilt walk in my ways, to keep my statutes and my commandments, as thy father David did walk, then I will lengthen thy days.