1 Timothy 6:17:

Charge them that are rich in this world, that they be not highminded, nor trust in uncertain riches, but in the living God, who giveth us all things richly to enjoy;

See also:

Who You Are and What You Have
Why Are You Here?
Objection: If You Suffer More in This Life, You Get a Greater Reward in Heaven
Objection: Teaching Grace Gives People a License to Sin