Walk through Amos, verse by verse, with the great Bible Commentaries of Matthew Henry (1662 - 1714) & Adam Clarke (1760 - 1832)
4:3
And ye shall go out at the breaches, every cow at that which is before her; and ye shall cast them into the palace, saith the LORD. KJV
{And ye shall go out by the openings, one against another, and ye shall be cast forth into Harmon, saith the Lord.} Wycliffe's Bible
And ye shall go out at the breaches - Probably the metaphor is here kept up. They shall be caught by the hooks, or by the nets; and though they may make breaches in the latter by their flouncing when caught, they shall be taken out at these very breaches; and cast, not in the palace, but into a reservoir, to be kept awhile, and afterwards be taken out to be destroyed.