'Take Heed' in the Bible

You shall set barriers for the people all around [the mountain], saying, ‘Beware that you do not go up on the mountain or touch its border; whoever touches the mountain must be put to death.

Now concerning everything which I have said to you, be on your guard; do not mention the name of other gods [either in a blessing or in a curse]; do not let such speech be heard [coming] from your mouth.

Watch yourself so that you do not make a covenant (solemn agreement, treaty) with the inhabitants of the land into which you are going, or it will become a [dangerous] trap among you.