'Be Careful' in the Bible

So be careful how you listen; for whoever has [a teachable heart], to him more [understanding] will be given; and whoever does not have [a longing for truth], even what he thinks he has will be taken away from him.”

Be careful, therefore, that the light that is in you is not darkness.

He said, “Be careful and see to it that you are not misled; for many will come in My name [appropriating for themselves the name Messiah which belongs to Me alone], saying, ‘I am He,’ and, ‘The time is near!’ Do not follow them.