James 5:19-20
My brothers, if anyone among you wanders from the truth and someone brings him back, let him know that whoever brings back a sinner from his wandering will save his soul from death and will cover a multitude of sins.

The gospel is not merely an introductory message to Christianity--it is the message of Christianity, and the believer would do well to give his life in the pursuit of knowing its glory and making its glory known.
Paul Washer