תּלמוד אויף משלי 2:3

Who dreams of having intercourse with his mother may hope for understanding; as it is said, "Yea, thou wilt call understanding 'mother'" (Prov. ii. 3). [Who dreams] of having intercourse with a betrothed maiden may hope for Torah, as it is said, "Moses commanded us a law [Torah], an inheritance of the congregation of Jacob" (Deut. xxxiii. 4) — read not morashah "an inheritance" but me'orasah "betrothed maiden." Who dreams of having had intercourse with his sister may hope for wisdom ; as it is said, "Say unto wisdom, thou art my sister" (Prov. vii. 4). Who dreams of having had intercourse with a married woman is assured that he is a son of the world to come ; but this applies only if he was not acquainted with her and did not think of her during the evening.