2 Peter 1:8
For if these things be in you, and abound, they make you that you shall neither be barren nor unfruitful in the knowledge of our Lord Jesus Christ.
2 Timothy 2:21
If a man therefore purge himself from these, he shall be a vessel unto honor, sanctified, and fit for the master's use, and prepared unto every good work.
Can a man be profitable unto God, as he that is wise may be profitable unto himself?
I beseech you for my son Onesimus, whom I have begotten in my bonds:
Who in time past was to you unprofitable, but now profitable to you and to me:
2 Timothy 4:11
Only Luke is with me. Take Mark, and bring him with you: for he is profitable to me for the ministry.