Boast not yourself of tomorrow; for you know not what a day may bring forth.
All Commentaries on Proverbs 27:1 Go To Proverbs 27
Caesarius of Arles
Therefore let us love our enemies. Perhaps the person who is your friend today will commit such sins that he cannot be with you in eternal life, “for you know not what tomorrow may bring.” On the contrary, your enemy may be converted to repentance in such a way that he merits to be your fellow citizen in that heavenly Jerusalem; in fact, he might even become greater than you.