webster...
You are correct -- we know that it is true because Scripture tells us that it is so.
The amalekites were a particularly evil people in the sight of God, and they sealed their fate when they launched an unprovoked attack on the children of Israel -- literally. The amalekites avoided attacking the army of Israel, and instead fell upon the stragglers, the weak, and the children who lagged behind the rest of the group, and they inflicted a great slaughter on them. For that, God pronounced a great judgement against them.
mlsoft