If you have begun to act well, do not turn back through the constraint of the enemy, for through your endurance the enemy is destroyed. Those who put out to sea at first sailed with a favourable wind; then the sails spread, but later the wind becomes adverse. Then the ship is tossed by the waves and is no longer controlled by the rudder. But when in a little while there is calm, and the tempest dies down, then the ship sails on again. So it is with us, when we are driven by the spirits who are against us; we hold to the cross as our sail and so we can set a safe course.

[Amma Syncletica, Apophthegmata Patrum]