When we consider the properties of fire, we realize that it is an accurate description of grace. Fire has brightness in appearance, warmness of effect, quickness of movement. In the same way, grace shines because of knowledge, warms through love, enkindles –and moves as a result of prayerfulness. Grace shines because of the knowledge through which God provides light for our eyes and shows us the path stretching homewards… Grace warms through love. It is through love that God arouses our hearts… Grace stretches and moves upwards as a result of prayerfulness which lifts the heart towards higher aims… Without this fire, there is no life. Consequently everyone should exert himself in order to possess this.
–Saint Bonaventure (1221-1274)