1 Not of compulsion is the doctrine; of free-will is the word of life. Whoso is willing to hear the doctrine, let him cleanse the field of his will that the good seed fall not among the thorns of vain enquirings. If you would heed the word of life, cut yourself off from evil things; the hearing of the word profits nothing to the man that is busied with sins. If you will to be good, love not dissolute customs. First of all, trust in God, and then hearken to His law.
Source: On Admonition and Repentance (New Advent)