Literally, “together,” or “at the same time.” Since the psalmist’s mind is at peace, he can lie down and sleep calmly. Confidence in God gives assurance of sleep. The two go hand in hand. This condition is the counterpart of the experience described in Ps. 3:5, in which the psalmist, in the morning, reflected that God had permitted him to sleep, although fearful enemies surrounded him; now, in the evening, he goes a step further and lies down serenely in the consciousness that, although he is still surrounded by his enemies, God will give him the gift of quiet and restful sleep (see Prov. 3:24).

 The psalmist expresses his realization that to God alone he is indebted for his safety through the night. What confidence: to know that he will be kept safely, and to recognize that he owes this safekeeping entirely to his God. The Christian who shares the confidence of the psalmist need have no fear during either the slumbers of the night or the duties of the day. The thought of v. 8 is the keynote of 121.

 There is a suggestion that as a part of public worship this psalm may have been sung in the Temple as follows: vs. 1-4 during the preparation for sacrifice; vs. 5, 6 during the offering; vs. 7, 8 after the sacrifice as an assurance of acceptance.