The following is an excerpt from a new post at Abiding Quaker, titled "His Seed Remaineth."

In asking that his disciples be kept from the evil, Jesus is asking that the inward condition of their souls be kept inviolate and uncorrupted by the evil that will—without question—assault them. It is the soul’s condition for which Jesus prays, that nothing in his disciples give foothold to the prince of the power of the air (Eph. 2:2); i.e. that his disciples heed no temptation, that they forfeit no blessedness.

The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light (Mt. 6:22).