The apple of the eye evidently refers to the pupil, the source of sight. With this figure, David was asking God to keep him in the center of His vision, not to let him out of His sight but to keep His eye on him. David also expressed his need for God"s careful protection, using the image of a bird protecting its young under its wings (cf. Deuteronomy 32:10-11; Ruth 2:12; Matthew 23:37). [source][source][source]
Context Summary
Psalms 17:1-15 - God's True Servants Safely Kept
This also dates from the Sauline persecutions. In the earlier verses David protests his innocence, pleads for deliverance from his foes, and ends with glad anticipation of the vision of God. The psalm may have been composed for use at eventide; two at least of its verses point in that direction, Psalms 17:3; Psalms 15:1-5.
What a comfort it is to appeal from the accusations of men to the judgment-bar of God! Yet our sufferings at their hands are God's smelting-furnace. The Hebrew word translated tried is "melted," Psalms 17:3. But we cannot be kept without constant use of God's Word, Psalms 17:4. And then how safe we are! The apple of the eye-that is, the pupil-is defended by eye lash, lid, brow, bony socket, and uplifted arm. Thy wings, see Deuteronomy 32:11.
Note the contrast between Psalms 17:14 and Psalms 16:5; Psalms 16:11. The worldly are filled with this world-I with thee. They look for the things of this life-I for the unseen and eternal. They are satisfied with children-I with thy likeness. [source]
Chapter Summary: Psalms 17
1David, in confidence of his integrity, craves defense of God against his enemies 10He shows their pride, craft, and eagerness 13He prays against them in confidence of his hope
What do the individual words in Psalms 17:8 mean?
Keep meas the appleofYour eyeunder the shadowof Your wingsHide me