Now listen, you who say,
"Today or tomorrow we will go to this or that city, spend a year there, carry on business and make money."Why, you do not even know what will happen tomorrow. What is your life? You are a mist that appears for a little while and then vanishes.
Instead, you ought to say,
"If it is the Lord's will, we will live and do this or that."As it is, you boast and brag. All such boasting is evil.
Anyone, then, who knows the good he ought to do and doesn't do it, sins.
James 4:13-17 (NIV)