Sometimes we try hard to practice pure prayer, and cannot; but it happens also that we do not compel ourselves, yet the soul prays with purity. The first results from our infirmity, the second, from grace from above, which thus calls us to seek purity of soul and teaches us, in each case, not to ascribe it to ourselves if our prayer is pure, but to recognize in this a gift of the Giver. “We know not what we should pray for as we ought.” [Romans 8:26] When we try to make our prayer pure and cannot, but are enveloped in darkness, let us moisten our cheeks with tears and implore God to disperse the night of the battle and to let light shine in the soul.
–Saint Nilus of Sinai (d. 430)