The Certainty of His Judgment On Israel. It Will Be Such That It Will Be Inescapable (Amos 2:13-16).
Israel's judgment is now described in terms of being run over by a heavy cart, fully loaded, and it will be something from which there will be no escape. They will find themselves face to face with YHWH's steamroller. As a result they will find themselves fading in strength, and discover that neither their armaments nor their speed of foot nor their horses will save them. Even the most courageous warrior, will flee in panic in that day.
“Behold, I will press you in your place, as a cart presses that is full of sheaves.”
In the day of His judgment they will be squashed under the wheels of YHWH's anger, in the same way as a cart that is full of sheaves, and therefore very heavy, squashes anything that gets in its way, or tears up the ill-prepared road. Alternately the idea may be that they will get bogged down, as a cart that is full of sheaves gets bogged down on the ill-made road.
“And flight will perish from the swift, and the strong will not strengthen his force, nor will the mighty deliver himself,”
Nor will any natural advantage be of any use in that day, for the judgment will be inevitable on all. The swift runners will discover that they are too weak to run, those who are strong will be unable to call on their strength and make it work for them, and even the mighty warrior, or those mighty enough to employ powerful bodyguards, will be unable to deliver themselves, because of YHWH's displeasure at them. Note the contrast with Isaiah 41:28-29 for those with whom YHWH is pleased.
“Nor will he stand who handles the bow, and he who is swift of foot will not deliver himself, nor will he who rides the horse deliver himself,”
The bowman will discover in that day that his bow is of little use to him when he is on the run. The swift of foot will discover that they are not speedy enough to avoid YHWH's judgment. Those who have horses to flee on will discover that it will not avail them. They will be unable to deliver themselves. Once YHWH moves in to punish them, all their protective methods in which they have trusted will prove in vain.
“And he who is courageous among the mighty will flee away naked in that day, says YHWH.”
And even the bravest among the mighty warriors will flee in that day, flinging their armour and robes from them so that they can flee faster. But they will flee in vain (Amos 2:15). And it is a day that is certain for it is confirmed by the word of YHWH.
In fact on the death of Jeroboam II things would rapidly come to a head, and it would not be many years (another forty years or so) before Samaria would be in ruins, and the cream of the people would be transported to Assyria and Media (2 Kings 17:6; 2 Kings 15:29). The people no doubt thought that Amos was exaggerating. But they would soon discover that his words were only too true.