13 I suppose the thing is now made manifest to you my brethren: this great and most concerning secret and mystery. What is the force of charity, all Scripture does set forth; but I know not whether any where it be more largely set forth than in this Epistle. We pray you and beseech you in the Lord, that both what you have heard you will keep in memory, and to that which is yet to be said, until the epistle be finished, will come with earnestness, and with earnestness hear the same. But open ye your heart for the good seed: root out the thorns, that that which we are sowing in you be not choked, but rather that the harvest may grow, and that the Husbandman may rejoice and make ready the barn for you as for grain, not the fire as for the chaff.
Source: Homilies on the First Epistle of John (New Advent)