Psalms 140:12

The cause of the afflicted - Every person who is persecuted for righteousness' sake has God for his peculiar help and refuge; and the persecutor has the same God for his especial enemy.

I know that the Lord will maintain the cause of the afflicted - See the notes at Psalm 9:4. The psalmist here doubtless refers primarily to himself, as having a confident belief that the Lord would maintain "his" cause, or would defend "him." At the same time he makes the statement general, implying that what would be done to him would be done to all in similar circumstances. The idea is that God, in all his attributes, in all his providential arrangements, in all his interpositions on earth, would be found to be on the side of the oppressed, the afflicted, and the wronged. He has no attribute that can take part with an oppressor or a wrong doer. The wicked cannot come to him with the belief that he will be on their side: the righteous - the oppressed - the afflicted - can.

And the right of the poor - He will defend the right of the poor. Literally, "The judgment of the poor." That which will be just and right in their case.