The Selah which parts the first from the second strophe is probably a direction for an instrumental interlude while the singer pauses.
The second strophe (vv. 3, 4) is the utterance of faith, based on experience, laying hold of Jehovah as defence. By an effort of will the psalmist rises from the contemplation of surrounding enemies to that of the encircling Jehovah. In the thickest of danger and dread there is a power of choice left a man as to what shall be the object of thought, whether the stormy sea or the outstretched hand of the Christ. This harassed man flings himself out of the coil of troubles round about him and looks up to God. He sees in Him precisely what he needs most at the moment, for in that infinite nature is fulness corresponding to all emptiness of ours. "A shield around me," as He had promised to be to Abraham in his peril; "my glory," at a time when calumny and shame were wrapping him about and his kingdom seemed gone; "the lifter up of my head," sunk as it is both in sadness and calamity, since Jehovah can both cheer his spirit and restore his dignity. And how comes this sudden burst of confidence to lighten the complaining soul? Ver. 4 tells. Experience has taught him that as often as he cries to Jehovah he is heard. The tenses in ver. 4 express a habitual act and a constant result. Not once or twice, but as his wont, he prays, and Jehovah answers. The normal relation between him and Jehovah is that of frank communion; and since it has long been so and is so now, even the pressure of present disaster does not make faith falter. It is hard to begin to trust when in the grip of calamity, but feet accustomed to the road to God can find it in the dark. There may be an allusion to David's absence from sanctuary and ark in ver. 4. The expectation of being answered "from His holy hill" gains in pathetic force when the lovely scene of submissive sacrifice in which he sent back the Ark is recalled (2 Sam. xv. 25). Though he be far from the place of prayer, and feeling the pain of absence, the singer's faith is not so tied to form as to falter in the assurance that his prayer is heard. Jehovah is shield, glory, and strengthener to the man who cries to Him, and it is by means of such crying that the heart wins the certitude that He is all these. Again the instruments sound and the singer pauses.
The third strophe (vv. 5, 6) beautifully expresses the tranquil courage which comes from trust. Since sleeping and safe waking again in ordinary circumstances is no such striking proof of Divine help that one in the psalmist's situation would be induced to think especially of it and to found his confidence on it, the view is to be taken that the psalmist in ver. 5 is contemplating the experience which he has just made in his present situation. "Surrounded by enemies, he was quite safe under God's protection and exposed to no peril even in the night" (Riehm, in Hupfeld _in loc._). Surely correspondence with David's circumstances may be traced here. His little band had no fortress in Mahanaim, and Ahithophel's counsel to attack them by night was so natural that the possibility must have been present to the king. But another night had come and gone in safety, disturbed by no shout of an enemy. The nocturnal danger had passed, and day was again brightening.
They were safe because the Keeper of Israel had kept them. It is difficult to fit this verse into the theory that here the persecuted Israelitish Church is speaking, but it suits the situation pointed to in the superscription. To lie down and sleep in such circumstances was itself an act of faith, and a sign of the quiet heart which faith gives. Like Christ on the hard wooden "pillow" during the storm, or like Peter sleeping an infant's sleep the night before his purposed execution, this man can shut his eyes and quiet himself to slumber, though "ten thousands have set themselves against him." They ring him round, but cannot reach him through his shield. Ver. 6 rises to bold defiance, the result of the experience in ver. 5. How different the tone of reference to the swarms of the enemy here and in ver. 1! There the psalmist was counting them and cowering before them; here their very number is an element in his triumphant confidence. Courage comes from thinking of the one Divine Ally, before whom myriads of enemies are nothing. One man with God to back him is always in the majority. Such courage, based on such experience and faith, is most modest and reasonable, but it is not won without an effort of will, which refuses to fear, and fixes a trustful gaze not on peril, but on the protector. "I will not be afraid" speaks of resolve and of temptations to fear, which it repels, and from "the nettle danger plucks the flower" _trust_ and the fruit _safety_. Selah does not follow here. The tone of the strophe is that of lowly confidence, which is less congruous with an instrumental interlude than are the more agitated preceding strophes. The last strophe, too, is closely connected with the third, since faith bracing itself against fear glides naturally into prayer.