Albert Barnes Commentary Psalms 139:9

"If I take the wings of the morning, And dwell in the uttermost parts of the sea;" — Psalms 139:9 (ASV)

If I take the wings of the morning - literally, “I will take the wings of the morning.” That is, I will take this as a hypothetical case; I will imagine what would occur if I were able to take for myself the wings of the morning and attempt to escape “by flight” from the presence of God, or go where he could not pursue me, or where he would not be. The “wings of the morning” evidently mean that by which the light of the morning “seems to fly”—the most rapid object known to us. It should not be assumed that the psalmist had an idea of the exact velocity of light, but for him, that was the most rapid object known; and his language is not the “less” striking because the laws of its flight have become accurately known.

The word rendered “morning” refers to the dawn—the daybreak—the Aurora—the “first” beams of the morning light. The beams of light are in fact no swifter then than at any other time of the day, but they seem to be swifter, as they so quickly penetrate the darkness.

And dwell in the uttermost parts of the sea - The end of the sea; that is, the “west,” as the sea referred to undoubtedly is the Mediterranean, which was west of Palestine, and which became another name for the west. The idea is that if he could fly with the rapidity of light and could be in an instant over the sea, even beyond its remotest border, still God would be there before him. He could not escape from the divine presence.