Saul is the law of nature which was allotted by God to hold sway over nature in the beginning. When he trangressed the commandment through disobedience by sparing Agag the king of Amalek, that is, the body, and lapsing into the passions, he was displaced in the kingship to allow David to take charge of Israel, that is, the Law of the Spirit which begets the peace which splendidly builds for God the temple of contemplation.
Samuel is interpreted as “obedience to God”. So long, then, as the Word exercises the priesthood in us by obedience, even though Saul should spare Agag (i.e. earthly intention), the Word as priest is jealous in thus slaying him and smites the mind which is prone to sin by putting it to shame as a companion warrior of divine righteousness. (Chapters on Knowledge 53-54)