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,.... Who being the strong and mighty God was able to deliver and save him, as well as to plead his cause; and was the author and giver of strength, natural and spiritual, to him; and was the strength of his heart, life and salvation; and is a good reason why he committed his cause unto him;
why doest thou cast me off? this is the language of unbelief: it being what was not in reality, only in appearance: the psalmist was ready to conclude he was cast off and rejected of God, because he was afflicted and left in a desolate condition by him, and he did not immediately arise to his help and deliverance, and had withdrawn the light of his countenance from him; but God does not cast off or reject any of his people; they always continue in his love, and in his covenant, and in the hands of his Son; they are always in his sight and family, and shall never perish eternally; and whoever casts them off, or casts them out, he will not;
why go I mourning because of the oppression of the enemy?
See Gill on "Psalms 42:9".