He only [is] my rock and my salvation
 (See Gill on Psalms 62:2); 
 [he is] my defence;
 these epithets of God are repeated, to strengthen his faith and hope in him, and to encourage a patient waiting upon him; 
 I shall not be moved;
 neither greatly, nor at all; his faith gets fresh strength and rigour, the more he considers God as his rock, salvation, defence, and refuge; (See Gill on Psalms 62:2).