What does Amos 7:13 mean?

Then Amaziah the priest of Bethel sent to Jeroboam king of Israel, saying, “Amos has conspired against you in the middle of the house of Israel. The land is not able to bear all his words.

For Amos says, ‘Jeroboam will die by the sword, and Israel shall surely be led away captive out of his land.’”

Amaziah also said to Amos, “You seer, go, flee away into the land of Judah, and there eat bread, and prophesy there:

Then Amos answered Amaziah, “I was no prophet, neither was I a prophet’s son; but I was a herdsman, and a farmer of sycamore figs;

and Yahweh took me from following the flock, and Yahweh said to me, ‘Go, prophesy to my people Israel.’

Now therefore listen to Yahweh’s word: ‘You say, Don’t prophesy against Israel, and don’t preach against the house of Isaac.’