Jamieson, Fausset and Brown on Ephesians 5:10

10. Proving--construed with "walk" (Ep 5:8; Ro 12:1, 2). As we prove a coin by the eye and the ear, and by using it, so by accurate and continued study, and above all by practice and experimental trial, we may prove or test "what is acceptable unto the Lord." This is the office of "light," of which believers are "children," to manifest what each thing is, whether sightly or unsightly.