ישעיהו נב:ד פירוש: רש״י ואבן עזרא

My people first went down to Egypt The Egyptians had somewhat of a debt upon them, for they served for them as their hosts and sustained them, but Assyria oppressed them for nothing and without cause.

My people went down, etc. Many evils came over my people from the beginning; for when, long ago, they went down to Egypt to sojourn there, they were oppressed.

באפס Without cause. For nothing. And the Assyrian without cause oppressed them. This refers to the exile of the ten tribes.