For thou art the God of my strength: why dost thou cast me off? why go I mourning because of the oppression of the enemy?
For thou art the God of my strength - literally, 'my fortress-God;' i:e., my protecting God; in Psalms 42:9, "God, my rock." Compare Psalms 27:1; Psalms 31:4; Psalms 37:39.
Why go I mourning because of the oppression of the enemy? - (Psalms 42:9.) The contrast between God's relation to him as his fortress- God, and the sufferer's present mourning, is the ground of his prayer for rectifying such an anomaly, by delivering him.