Albert Barnes Commentary Isaiah 29:19

"The meek also shall increase their joy in Jehovah, and the poor among men shall rejoice in the Holy One of Israel." — Isaiah 29:19 (ASV)

The meek - The word ‘meek’ usually refers to those who are patient in the reception of injuries, but the Hebrew word used here (ענוים ‛ănâviym) properly means the oppressed, the afflicted, the unhappy (Psalms 9:13; Psalms 10:12, 17; Proverbs 3:34; Isaiah 11:4). It usually involves the idea of humility or “virtuous suffering” (Psalms 37:11; Psalms 69:33). Here it may denote the pious of the land who were oppressed, and subjected to trials.

Shall increase - Margin, as in Hebrew, ‘Add.’ It means, that they should greatly rejoice in the Lord. They should see the evidence of the fulfillment of his predictions; they should see the oppressors punished (Isaiah 29:20–21), and Yahweh coming forth to be their protector and defender (Isaiah 29:22–24).

And the poor among men - The poor people; or the needy. Doubtless the idea is that of the pious poor; those who feared God, and who had been subjected to the trials of oppression and poverty.