Saint Anselm.

“If you want to be certain of being in the number of the Elect, strive to be one of the few, not one of the many. And if you would be quite sure of your salvation, strive to be among the fewest of the few; that is to say, do not follow the great majority of mankind, but follow those who enter upon the narrow way, who renounce the world, who give themselves to prayer, and who never relax their efforts by day or night, so that they may attain everlasting blessedness.” -Saint Anselm, Father and Doctor of the Church