God is Light

God is like light in that He is the source of all truth and exposes truth. He cannot be mixed with darkness, which means fellowshipers with Him do not walk in the darkness (that is, live in a manner that is inconsistent with the truth about themselves and about God). Walkers in the light do that (step into darkness), but they do not walk in the darkness because they return to the light (repentance). Return by seeking restored intimacy with God. You know it is time to stop grieving and return to rejoicing when you feel the joy, peace, etc. of His presence.