Tobit 6:18 CPDV

¹⁶  Then the Angel Raphael said to him: 'Listen to me, and I will reveal to you who they are, over whom the demon can prevail.

¹⁷  For example, those who receive marriage in such manner as to exclude God from themselves and from their mind, and in such a manner as to empty themselves to their lust, like the horse and mule, which have no understanding, over them the demon has power.

¹⁸  But you, when you will have accepted her, enter the bedroom and for three days keep yourself continent from her, and empty yourself to nothing other than prayers with her.

¹⁹  Moreover, on that night, burn the liver of the fish like incense, and the demon will be put to flight.

²⁰  In truth, on the second night, you will become ready to receive a physical union like that of the holy Patriarchs.