Thus saith the Lord God: this solemnly attesteth the certainty of the thing. The city that went out by a thousand, that sent out one thousand soldiers as the quota they were assessed at to help against an invader, shall leave a hundred; shall lose nine parts of ten, so great shall the slaughter be which the prevailing enemy shall make upon Israel; and here the prophet useth a certain number to express an uncertain; or proverbially, scarce a tenth man shall escape. That which went forth by a hundred shall leave ten, to the house of Israel; the kingdom of the ten tribes; and this perhaps may refer backward to Jehoahaz's time, 2Ki 13; to be sure it is fulfilled in the wars of Shalmaneser and the taking Samaria.
Related Commentaries of Amos 5:3
Amos 5:3
3 For thus saith the Lord GOD; The city that went out by a thousand shall leave an hundred, and that which went forth by an hundred shall leave ten, to the house of Israel.