The third vow, conversatio morum , can literally be translated as "conversion of life", although its exact meaning is much debated, so it is often left in its Latin form. It means being faithful to the monastic way, being true to a single-hearted quest for God.
Although monks do not take them explicitly, it encompasses the other traditional vows which all religious profess - chastity and poverty. We do not marry to be free for God, and our life should be marked by simplicity and frugality, avoiding an ever-increasing accumulation of possessions but holding what we have in common.
If we do remain faithful to the monastic way, St Benedict promises us that "as we progress in our monastic life and our faith the heart expands and we run along the way of God's commandments with a delight of love that cannot be described"