"Though he slay me, yet will I trust in him."
"This is a high expression of faith, and what we should all labour to come up to—to trust in God, though he slay us, that is, we must be well pleased with God as a friend even when he seems to come forth against us as an enemy. We must believe that all shall work for good to us even when all seems to make against us. We must proceed and persevere in the way of our duty, though it cost us all that is dear to us in this world, even life itself. We must depend upon the performance of the promise when all the ways leading to it are shut up. We must rejoice in God when we have nothing else to rejoice in, and cleave to him, yea, though we cannot for the present find comfort in him. In a dying hour we must derive from him living comforts; and this is to trust in him though he slay us."
Matthew Henry on Job 13