John Gill Commentary 1 Kings 2:43

"Why then hast thou not kept the oath of Jehovah, and the commandment that I have charged thee with?" — 1 Kings 2:43 (ASV)

Why then have you not kept the oath of the Lord
Which was made by him, and in his presence, and in which he was appealed to, and so by not keeping it was guilty of perjury:

and the commandment that I have charged you with ?
and so guilty of disobedience to him as his sovereign; for which two reasons he ought to die.