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, Eph 6:17, Th1 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, Isa 59:16.