Matthew Poole and continuators on 1 Samuel 15:3

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 asse .

Both Persons and Goods, Kill all that live, and Consume all things without life, for I will have no Name nor Remnant of that People whom long since I have Cursed and Devoted to utter Destruction.

Shew no Compassion or Favour to any of them. The same thing repeated to prevent mistake, and oblige Saul to the exact performance hereof; or, to leave him without excuse, in case of neglect.

For their Parents Crime and Punishment: which was not unjust, because God is the Supreme Lord and giver of Life, and can require his own when he pleaseth; Infants also are Born in sin, Psal. 51. 5. and therefore liable to God's wrath, Eph. 2. 3. and to death, Rom. 5. 12, 14. Their death also was rather a Mercy than a Curse to them, as being the occasion of preventing the vast increase of their Sin and Punishment.

Which being all made for Man's benefit, it is not strange nor unjust, if they suffer with him, and for him, and for the instruction of Mankind.