Hear my voice, O God, in my prayer - The use of the word voice here would seem to imply that this was audible prayer, or that, though alone, he gave utterance to his petitions aloud. We have this same use of the word often in the Psalms, making it probable that even private prayers were uttered in an audible manner. In most cases, when there is no danger of being overheard, or of its being construed as ostentation or Pharisaism, this is favorable to the spirit of secret devotion. Compare the notes at Daniel 6:10. The word here rendered prayer means properly speech, discourse; then, complaint; then, meditation. It is most commonly rendered complaint. See Job 7:13; Job 9:27; Job 10:1; Job 21:4; Psalms 55:2 (notes); Psalms 102 (Title); Psalms 142:2. It refers here to a state of mind caused by trouble and danger, when the deep meditation on his troubles and dangers found expression in audible words - whether those words were complaint or petition. As there are no indications in the psalm that David was disposed to complain in the sense of blaming God, the proper interpretation here is that his deep meditations took the form of prayer.
Preserve my life from fear of the enemy - Either Saul or Absalom. He prayed that his life might be made so secure that he would not have occasion to be afraid of his enemy.