Yea, the darkness hides not from you; but the night shines as the day: the darkness and the light are both alike to you.
All Commentaries on Psalms 139:12 Go To Psalms 139
Augustine of Hippo
AD 430
11. "For darkness shall not be darkened by Thee" (ver. 12). Do not thou then darken thy darkness; God darkeneth it not, but enlighteneth it yet more; for to Him is said in another Psalm, "Thou, Lord, shalt light my candle: my God shall enlighten my darkness." But who are they who "darken their darkness," which God darkeneth not? Evil men, perverse men; when they sin, verily they are darkness; when they confess not their sins which they have committed but go on to defend them, they "darken their darkness." Wherefore now if thou hast sinned thou art in darkness, but by confessing thy darkness thou shall obtain to have thy darkness lightened; by defending thy darkness, thou shall "darken thy darkness." And where wilt thou escape from double darkness, who wast in difficulty in single darkness? ...Let us not "darken our darkness" by defending our sins, and "the night shall be light in our delight."
12. "And night shall be lightened as the day." "Night, as the day." "Day" to us is worldly prosperity, night adversity in this world: but, if we learn that it is by the desert of our sins that we suffer adversities, and our Father's scourges are sweet to us, that the Judge's sentence may not be bitter to us, so shall we find the darkness of this night to be, as it were, the light of this night. ...But when Christ our Lord has come, and has dwelt in the soul by faith, and promised other light, and inspired and given patience, and warned a man not to delight in prosperity or to be crushed by adversity, the man, being faithful, begins to treat this world with indifference; not to be lifted up when prosperity befalls him, nor crushed when adversity, but in all things to praise God, not only when he aboundeth, but also when he loseth; not only when he is in health, but also when he is sick. ..."As is His darkness, so is also His light." His darkness overwhelms me not, because His light lifts me not up.