The particle אך, ach, in the second verse, I would render in the same way as in the first. The believer triumphs in one encounter with temptation only to enter upon another; and here David, who appeared to have emerged from his distress, shows that he had still to struggle with remaining difficulties. We meet with the same particle no fewer than six times throughout the psalm. This, too, may explain the many titles which he applies to God, each of which is to be considered as a foil by which he would ward off the attacks of the tempter. The expression in the close of the verse, I shall not be greatly moved, implies his persuasion that he might be overtaken with afflictions, (for he was well aware that he could claim no exemption from the common lot of humanity,) but his conviction, at the same time, that these would not overwhelm him, through the good help of God. We shall find him saying afterwards, in so many words, I shall not fall; perhaps because he felt, as he advanced in prayer, that he had greater boldness in despising affliction. Or the expressions may be taken as synonymous in the two places. The truth itself is unquestionable. The believer may be overthrown for a time; but as he is no sooner cast down than he is raised up again by God, he cannot properly be said to fall. He is supported by the Spirit of God, and is not therefore really prostrated and overcome.