1 Samuel 15:3
"Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass."
Cross References (ranked by relevance)
And when he looked on Amalek, he took up his parable, and said, Amalek was the first of the nations; but his latter end shall be that he perish for ever.
Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him.
And Nob, the city of the priests, smote he with the edge of the sword, both men and women, children and sucklings, and oxen, and asses, and sheep, with the edge of the sword.
Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me;