Samuel said, As your sword has made women childless, so shall your mother be childless among women. Samuel hewed Agag in pieces before Yahweh in Gilgal.
Samuel spoke what the writer recorded in 1 Samuel 14:22-23 in poetic form, indicating to all that God had inspired what he was saying. God frequently communicated oracles through the prophets in such exalted speech (cf. Genesis 49; Deuteronomy 33; et al.). These classic verses prioritize total obedience and worship ritual for all time. God desires reality above ritual. Sacrificing things to God is good, but obedience is "better" because it involves sacrificing ourselves to Him. The spared animals Saul offered to God were voluntary sacrifices.