Matthew 6:16

ὅταν δὲ : transition to a new related topic. σκυθρωποί, of sad visage, overdone of course by the “actors”. Fasting, like prayer, was reduced to a system; twice a week in ordinary Pharisaic practice: Thursday and Monday (ascent and descent of Moses on Sinai), artificial gloom inevitable in such circumstances. In occasional fasting, in circumstances of genuine affliction, the gloom will be real (Luke 24:17). ἀφανίζουσιν ὅπως φανῶσιν, a play upon words, may be rendered in English “they disfigure that they may figure”. In German: Unsichtbar machen, sichtbar werden (Schanz and Weiss).