If a man has sinned and denies it, saying: 'I have not sinned,' do not reprimand him; for that will discourage him. But say to him, 'Do not lose heart, brother, but be on guard in future,' and you will stir his soul to repentance. Poemen
We must always be on guard lest, under the pretext of keeping one commandment, we be found breaking another. Basil of Caesarea
I can be on guard against my enemies, but God deliver me from my friends! Charlotte Brontë
Wine is a treacherous friend who you must always be on guard for. Christian Nestell Bovee
Whenever a government feels the need of promising peace and prosperity to its citizens by means of a proclamation, it is time to be on guard and expect the opposite. Ivo Andrić
You can't sleep and be on guard. Sicilian Proverb