'Be on Your Guard' in the Bible
So be on your guard that the very source of light in you is not darkness.
In the meanwhile, when so many thousands of the people had gathered that they were trampling on one another, Jesus commenced by saying primarily to His disciples, Be on your guard against the leaven (ferment) of the Pharisees, which is hypocrisy [producing unrest and violent agitation].
And to the people He said, "Take care, be on your guard against all covetousness, for no one's life consists in the superabundance of his possessions."
Pay attention and always be on your guard [looking out for one another]. If your brother sins (misses the mark), solemnly tell him so and reprove him, and if he repents (feels sorry for having sinned), forgive him.
"Be on your guard against the Teachers of the Law, who delight to walk about in long robes, and like to be greeted in the streets with respect, and to have the best seats in the Synagogues, and places of honor at dinner.
And He said, Be on your guard and be careful that you are not led astray; for many will come in My name [ appropriating to themselves the name Messiah which belongs to Me], saying, I am He! and, The time is at hand! Do not go out after them.
But take heed to yourselves and be on your guard, lest your hearts be overburdened and depressed (weighed down) with the giddiness and headache and nausea of self-indulgence, drunkenness, and worldly worries and cares pertaining to [the business of] this life, and [lest] that day come upon you suddenly like a trap or a noose;
"So be on your guard at all times, praying that you may be worthy to escape these things that shall come to pass, and to take your stand in the presence of the Son of man."