O God the Lord ... - literally, "Yahweh, Lord, the strength of my salvation" The word rendered "God," in the original, is יהוה Yahweh. The address is to Yahweh as the Lord; that is, as the supreme Ruler - who presides over all things. Him the psalmist acknowledged as "his" Lord and Ruler. The phrase "the strength of my salvation" means the strength or power on which my safety depends. I have no other hope of deliverance but in thee.

Thou hast covered my head in the day of battle - Thou hast been a shield unto me. Literally, "In the day of arms," or of armor, 1 Kings 10:25; Ezekiel 39:9-10.

Thou hast covered my head - Not only when I fought with the proud blaspheming Philistine; but in the various attempts made against my life by my sworn enemies.

O God the Lord, the strength of my salvation,.... Temporal and spiritual, which he was able to effect; the mighty God and mighty Saviour: and this encouraged David to believe he should have deliverance; and this secured, confirmed, and established it to him; and to which he was the more induced by what experience he had had of the divine goodness to him, as follows:

thou hast covered my head in the day of battle; with the helmet of salvation, as Kimchi, Aben Ezra, and Arama observe; which, in a spiritual sense, is to a believer the hope of salvation, Ephesians 6:17, 1 Thessalonians 5:8; a defensive weapon to him; and protects him while he is engaging with his spiritual enemies in this his state of warfare, sin, Satan, and the world. Perhaps David may have respect to the divine protection of him, when he fought with Goliath. Salvation was Christ's helmet, when he engaged with all his and our enemies; even with all the powers of darkness, and obtained deliverance for us, Isaiah 59:16.

O GOD the Lord, the strength of my salvation, thou {e} hast covered my head in the day of battle.

(e) He calls to God with lively faith, being assured of his mercies, because he had before time proved, that God helped him ever in his dangers.

7. day of battle-literally, "of armor," that is, when using it.

140:1-7 The more danger appears, the more earnest we should be in prayer to God. All are safe whom the Lord protects. If he be for us, who can be against us? We should especially watch and pray, that the Lord would hold up our goings in his ways, that our footsteps slip not. God is as able to keep his people from secret fraud as from open force; and the experience we have had of his power and care, in dangers of one kind, may encourage us to depend upon him in other dangers.