Proving what is acceptable unto the Lord.
Proving - construed with "walk" (Ephesians 5:8; Romans 12:1-2). As we prove a coin by the eye and ear, and by using it; so, by accurate study and experimental trial, we may test 'what is acceptable unto the Lord;' which last is the Christian's one criterion in estimating things. "Light," of which believers are "children," manifests what each thing really is.