James 1:17 declares that with the Father of lights there is no variation or shadow of turning. The term belongs to astronomical vocabulary, describing the apparent movement or changing of celestial bodies. James uses this imagery to contrast God's unchanging nature with the variability of created lights like sun and moon, which shift position and cast moving shadows. While heavenly bodies have 'turnings'—solstices, phases, eclipses—God remains constant in character and purpose. The metaphor assures believers that divine goodness is utterly reliable.