FAITH IS THE BEGINNING, the foundation and the root of justification, and without faith it is impossible to please God and to be numbered among his sons.
It is the beginning because it establishes the first contact between ourselves and God, the Author of the supernatural order.
The first thing is to believe in God. It is the foundation inasmuch as all the other virtues, including charity, presuppose faith, and are established upon it as an edifice on its foundation.
Without faith it is impossible to hope or to love. It is the root, because in it, when informed by charity, all the other virtues live. When informed by charity, faith produces, among other things, two great effects in the soul: the filial fear of God which helps the soul keep it self from sin, and the purification of the heart which raises it to the heights and cleanses it of its affection for earthly things.
– Antonio Royo, O.P., & Jordan Aumann, O.P.