Death and life are in the power of the tongue, And those who love it will eat its fruit.  Proverbs 18:21
This makes me think of a Casting Crowns song that talks about "flattery leads to compramise".  This verse can pertain to the things that you let come out of your own mouth or even the things that come out of others' mouths. Such as foul language by friends, music, or even movies(it Will rub off on you), or even flattery for example.  Oh be careful little ears what you hear...Oh be careful little lips what you say...For the Father up above is looking down...
This really is a Life & Death situation. 
Follow this link to read more verses about "the tongue". There are many!