8 “Who savest them that hope in You from such as resist Your right hand:” from such as resist the favour, whereby You favour Me. “Keep Me, O Lord, as the apple of Your eye”: which seems very little and minute: yet by it is the sight of the eye directed, whereby the light is distinguished from the darkness; as by Christ's humanity, the divinity of the Judgment distinguishing between the righteous and sinners. “In the covering of Your wings protect Me.” In the defence of Your love and mercy protect Me. “From the face of the ungodly who have troubled Me”.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)