And they that know thy Name will put their trust in thee. "To know the Name of God is to know him according to his historical manifestation; when one hears him named, to call to remembrance all that he has done.
His name is the focus in which all the rays of his actions meet" (Hengstenberg). All who "know God's Name" in this sense will be sure to "put their trust in him," since his historical manifestation shows that he is thoroughly to he depended on.
For thou, Lord, hast not forsaken them that seek thee. Never in the past, so far as David knew, had God forsaken those who faithfully clung to him. They might be tried, like Job; they might be "hunted upon the mountains," like David himself; they might even have the sense of being forsaken (Psalms 22:1); but they were not forsaken nevertheless.
God "forsaketh not his saints; they are preserved for ever" (Psalms 37:28).