St. Francis has a thorough understanding of Aristotle and St. To deserve the name of a vice or a virtue, there must be an advance in an act and it must be habitual. St. Francis explains the distinction between mortal sin and venial sin and the danger of frequently committing venial sin. Since charity is infused and not acquired as natural habits are, charity can be lost by a single mortal sin. However, habits which are acquired solely by human acts can be lost by long neglect of such acts or by many acts contrary to this habit.
Charity is infused by the Holy Spirit in a moment.
It is also taken from us in an instant as soon as we turn away from the obedience we owe to God in grave matter. We need to reflect on this doctrine repeatedly taught by Pope John Paul II in answer to the widespread theory of the fundamental option and the mistaken notion that a single mortal sin does not destroy charity and does not incur the risk of losing heaven. We never lose any least part of it without losing all of it . This imperfect love which is reduced to a natural love, though salutary, may be dangerous. This is discussed in no uncertain terms.