But thou, O Lord, art a shield, &c.— David, in the midst of his distress, having recollected himself, immediately quiets his mind by trusting in God. By prayer he recommended himself to the divine protection; and so calmed his fears, that he quietly laid himself down, slept comfortably, and waked tranquil and easy, as if no danger surrounded him; and resolved that the most formidable combinations against him should not discourage and terrify him: Psalms 3:4-6. Thou art my glory, signifies "I rejoice "and glory in thy protection; as well knowing that thou "art able to restore me to my former dignity and power." To lift up the head, is the mark of prosperity, ease, and comfort, and of a mind elated and joyful in the possession of it. Thus Zophar speaks of the prosperous hypocrite, that his joy should endure but for a moment, though his head should reach up unto the clouds: Job 20:5-6. Something like Horace, Sublimi feriam sidera vertice; which Mr. Dacier interprets, J'apporterai mon superb front jusqu' aux cieux. When, therefore, David speaks of God as the lifter-up of his head, he means that God would remove his distresses, make him to triumph over all his enemies, and cause him to look up with cheerfulness and joy upon the full recovery of his prosperity and honours. Chandler.
Psalms 3:5-6. I laid me down and slept— It was an argument of settled courage, and shews the unspeakable advantage of a religious confidence in God, that David was able, in such distressing and dangerous circumstances, thus to lie down, calmly sleep, and wake in peace: but what cannot that man do, who is sustained of God, propped up by him, as the word סמךֶ samak properly signifies, by inspiring his mind with resolution and courage? Chandler.