Charles H. Spurgeon on Psalms 62:2

He only is my rock and my salvation. Sometimes a metaphor may be more full of meaning and more suggestive than literal speech: hence the use of the figure of a rock, the very mention of which would awaken grateful memories in the psalmists's mind. David had often lain concealed in rocky caverns, and here he compares his God to such a secure refuge; and, indeed, declares him to be his only real protection, all-sufficient in himself and never failing. At the same time, as if to show us that what he wrote was not mere poetic sentiment but blessed reality, the literal word salvation follows the figurative expression: that our God is our refuge is no fiction, nothing in the world is more a matter of fact. He is my defence, my height, my lofty rampart, my high fort. Here we have another and bolder image; the tried believer not only abides in God as in a cavernous rock; but dwells in him as a warrior in some bravely defiant tower or lordly castle. I shall not be greatly moved. His personal weakness might cause him to be somewhat moved; but his faith would come in to prevent any very great disturbance; not much would he be tossed about. Moved, as one says, "but not removed." Moved like a ship at anchor which swings with the tide, but is not swept away by the tempest. When a man knows assuredly that the Lord is his salvation, he cannot be very much cast down: it would need more than all the devils in hell greatly to alarm a heart which knows God to be its salvation.