Thou prevailest forever against him - Thou dost always show that thou art stronger than he is. He never shows that he is able to contend with God.
And he passeth - He cannot stand before thee, but is vanquished, and passes off the stage of being.
Thou changest his countenance - Possibly the allusion is to the change produced by death. The countenance that glowed with health and was flushed with beauty and hope - blooming as the rose - is made pale as the lily under the hand of God. What an affecting exhibition of the power of God!
And sendest him away - This language seems to be that of expectation that man would still live though he was sent away; but all his hopes on earth were blasted, and he went away from his friends and possessions to return no more.