First of all, friars are still different from monks as they both still exist in the Church. Monks take three vows of Obedience, Stability, and conversatio morum, a Latin term meaning fidelity to the monastic life (which includes Chastity and Poverty). Stability means remaining in one monastery for your entire life. Friars are mendicants, they are not vowed to one monastery, their vows are Chastity, Poverty, and Obedience, which are the three evangelical virtues that Our Blessed **** preached to those who would be perfect. THe monks primary occupation is to pray and to be perfect, the friars primary duty is to live the evangelical counsels in the world and whatever the particular charism of their Order is, for instance, the Dominicans charism is preaching.