'Be on Your Guard' in the Bible

Be on your guard against men, for they will turn you over to the courts and will flog you in their synagogues,

So you must be on your guard. I have warned you about it all beforehand.

So be on your guard that the very source of light in you is not darkness.

But ever be on your guard, so that your hearts may not be loaded down with self-indulgence, drunkenness, and worldly worries, and that day, like a trap, catch you unawares.

So ever be on your guard and always remember that for three years, night and day, I never ceased warning you one by one, and that with tears.

You too must be on your guard against him, for he has vigorously opposed my teaching.

So, dearly beloved, since you have been forewarned, you must always be on your guard against being led astray by the errors of lawless men, and so against falling away from your present firmness;