Albert Barnes Commentary Isaiah 16:4

"Let mine outcasts dwell with thee; as for Moab, be thou a covert to him from the face of the destroyer. For the extortioner is brought to nought, destruction ceaseth, the oppressors are consumed out of the land." — Isaiah 16:4 (ASV)

Let my outcasts - This may be understood as the language of Judea, or of God. ‘My outcasts’ may mean the exiles of Judea, or God may call them “His.” The sense is essentially the same. It denotes those who were fugitives, wanderers, exiles from the land of Judea, and who took refuge in the land of Moab; and God claims protection for them.

Dwell with you - Not dwell permanently, but sojourn (יגוּרוּ yāgûrû); let them remain with you as exiles, or let them find a refuge in your land.

Be you a shelter to them - A refuge, a hiding-place, a place of “secrecy” (סתר sêther).

From the face of the spoiler - This refers to the conqueror from whose desolating career they would seek refuge in the land of Moab. Who this “spoiler” would be is not known. It would seem to be some invader who was carrying desolation through the land of Judea.

It may be observed, however, that Lowth, by setting the vowel points aside, supposes that this should be read, ‘Let the outcasts of Moab sojourn with you, O Zion.’ Noyes concurs with this reading. But this interpretation seems to me not to suit the connection and the design, which is to persuade the Moabites to conciliate the favor of the Jews by affording a hiding-place to their fugitives.

For the extortioner is at an end - Literally, ‘There is an end, or there will be an end of the oppressor; or he will be lacking.’ The Chaldee renders it, ‘The enemy is at an end.’

The idea here seems to be that the oppressor in the land of Judea would not continue there always. The exiles of the Jews might soon return, and Judea would then be able to return kindness to Moab. Judea did not ask that her exiles should permanently abide in Moab, but asked only for a temporary refuge, with the certainty that she would soon be delivered from her oppressions and would then be able to furnish aid to Moab in return.

The oppressors are consumed - Or, ‘the treader down,’ he who has trodden down the nations shall soon be removed, and then, in turn, Judea will be able to repay the kindness which is now asked of Moab, in permitting her exiles to remain in their land.