1 Corinthians 9:24
Know ye not that they which run in a race run all, but one receiveth the prize? So run, that ye may obtain.
Note 12 at 1Co 9:24: Paul wasn't just content with finishing the race; he wanted to win. Selfish ambition is detrimental, but having ambition to advance the kingdom of God is commendable. God doesn't like lukewarmness (Re 3:16).