Matthew Henry on Deuteronomy 25:17-19

Let every persecutor and injurer of God's people take warning from the case of the Amalekites. The longer it is before judgement comes, the more dreadful will it be at last. Amalek may remind us of the foes of our souls. May we be enabled to slay all our lusts, all the corruptions both within and without, all the powers of darkness and of the world, which oppose our way to the blessed Saviour.