Adam Clarke on Psalms 28:1

O Lord my rock - צורי tsuri not only means my rock, but my fountain, and the origin of all the good I possess.

If thou be silent - If thou do not answer in such a way as to leave no doubt that thou hast heard me, I shall be as a dead man. It is a modern refinement in theology which teaches that no man can know when God hears and answers his prayers, but by an induction of particulars, and by an inference from his promises. And, on this ground, how can any man fairly presume that he is heard or answered at all? May not his inductions be no other than the common occurrences of providence? And may not providence be no more than the necessary occurrence of events? And is it not possible, on this skeptic ground, that there is no God to hear or answer? True religion knows nothing of these abominations; it teaches its votaries to pray to God, to expect an answer from him, and to look for the Holy Spirit to bear witness with their spirits that they are the sons and daughters of God.