'Be on Your Guard' in the Bible

Now concerning everything which I have said to you, be on your guard; and do not mention the name of other gods, nor let them be heard from your mouth.

Be on your guard before him and obey his voice; do not be rebellious toward him, for he will not pardon your transgression, since My name is in him.

“But be on your guard; for they will deliver you to the courts, and you will be flogged in the synagogues, and you will stand before governors and kings for My sake, as a testimony to them.

Then He said to them, “Beware, and be on your guard against every form of greed; for not even when one has an abundance does his life consist of his possessions.”

Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him.

You therefore, beloved, knowing this beforehand, be on your guard so that you are not carried away by the error of unprincipled men and fall from your own steadfastness,