The Lord is my rock - The idea in this expression, and in the subsequent parts of the description, is that he owed his safety entirely to God. He had been unto him as a rock, a tower, a buckler, etc. - that is, he had derived from God the protection which a rock, a tower, a citadel, a buckler furnished to those who depended on them, or which they were designed to secure. The word “rock” here has reference to the fact that in times of danger a lofty rock would be sought as a place of safety, or that men would fly to it to escape from their enemies. Such rocks abound in Palestine; and by the fact that they are elevated and difficult of access, or by the fact that those who fled to them could find shelter behind their projecting crags, or by the fact that they could find security in their deep and dark caverns, they became places of refuge in times of danger; and protection was often found there when it could not be found in the plains below. Compare Judges 6:2; Psalms 27:5; Psalms 61:2. Also, Josephus, Ant., b. xiv., ch. xv.
And my fortress - He has been to me as a fortress. The word fortress means a place of defense, a place so strengthened that an enemy could not approach it, or where one would be safe. Such fortresses were often constructed on the rocks or on hills, where those who fled there would be doubly safe. Compare Job 39:28. See also the notes at Isaiah 33:16.
And my deliverer - Delivering or rescuing me from my enemies.
My God - Who hast been to me a God; that is, in whom I have found all that is implied in the idea of “God” - a Protector, Helper, Friend, Father, Saviour. The notion or idea of a “God” is different from all other ideas, and David had found, as the Christian now does, all that is implied in that idea, in Yahweh, the living God.
My strength - Margin, “My rock” So the Hebrew, although the Hebrew word is different from that which is used in the former part of the verse. Both words denote that God was a refuge or protection, as a rock or crag is to one in danger (compare Deuteronomy 32:37), though the exact difference between the words may not be obvious.
In whom I will trust - That is, I have found him to be such a refuge that I could trust in him, and in view of the past I will confide in him always.
My buckler - The word used here is the same which occurs in Psalms 3:3, where it is translated “shield.” See the notes at that verse.
And the horn of my salvation - The “horn” is to animals the means of their defense. Their strength lies in the horn. Hence, the word is used here, as elsewhere, to represent that to which we owe our protection and defense in danger; and the idea here is, that God was to the psalmist what the horn is to animals, the means of his defense. Compare Psalms 22:21; Psalms 75:4-5, Psalms 75:10; Psalms 92:10; Psalms 132:17; Psalms 148:14.
And my high tower - He is to me what a high tower is to one who is in danger. Compare Proverbs 18:10, “The name of the Lord is a strong tower: the righteous runneth into it, and is safe.” The word used here occurs in Psalms 9:9, where it is rendered “refuge.” (Margin, “A high place.”) See the notes at that verse. Such towers were erected on mountains, on rocks, or on the walls of a city, and were regarded as safe places mainly because they were inaccessible. So the old castles in Europe - as that at Heidelberg, and generally those along the Rhine - were built on lofty places, and in such positions as not to be easily accessible.