EADY or not, here I come! In a way, that sentence sums up the message of God through Amos in this chapter. In short, He said to Israel, "Prepare to meet thy God!" (Amos 4:12).
There are many judgmental words in this chapter. In fact, there were many judgments that had already come upon Israel, but to no avail (vs. 9-10). God had tried starving them into submission (vs. 6). He had held back the rain (vs. 7-8). Notice the outstanding new threat though. God threatened to take them away with hooks (vs. 2). And, these are only representative of many other judgments (which Israel had brought upon for herself by her disobedience).
It is evident that God considered all of the warnings that He had given to Israel to be more than enough to give them a chance to change & to do right. In vs. 11 it is recorded that God described Israel's plight as "a firebrand plucked out of the burning." In other words, the judgment had already begun. The salvation of Israel would have to involve the cessation of punishment, because HE had already begun to punish them for their sins.