Psalm 34:11-14:

Come, ye children, hearken unto me: I will teach you the fear of the LORD.
What man is he that desireth life, and loveth many days, that he may see good?
Keep thy tongue from evil, and thy lips from speaking guile.
Depart from evil, and do good; seek peace, and pursue it.

Notes on Psalm 34:11-14:

You do not live a long life just by claiming “long life” promises.  If you’re a backbiter, a gossip, a reviler, or an evil speaker, don’t bother claiming long life.  If your tongue is going to slice and dice like a Ginsu knife, something else will most likely get cut – your lifespan.

See also:

Some of God’s Promises Have Conditions
Is There an Appointed Time for Each Person to Die?