Siman 230

(1.) Rabbi Naftali told that Rabbainu o.b.m. said it would be very good if a proper man had horses and would travel every so often with young men into some forest or the like, and there they would speak of awe of Heaven and engage in hisbodidus etc. For in the field and the forest it is very good for hisbodidus. And he told then of his conduct in the days of his youth — that he was accustomed to take a horse from his father-in-law's house and ride on the horse to some forest. And there he would dismount from the horse and tie it to some tree, and he would go inside the forest to do what he needed and engage in hisbodidus as was his custom. And many times the horse would untie itself and run away home to his father-in-law's house. And when they saw there that the horse had come back alone they were very worried and frightened — for they said he had certainly fallen from the horse, G-d forbid. And many times great rains fell upon him while he was in the forest, and afterwards he came home late at night or later. And I heard from his holy mouth many times that the main thing depends only on effort and exertion etc., and through this every person can come to great levels etc. And he said: "I can make a proper man — what they call a giter Yid — exactly like me."