Let’s make an important distinction between self-denial and penance. Self-denial is giving up creature comforts to work toward a worthy goal. Penance is self-punishment in hopes of earning God’s favor, which is absolutely, 100 percent impossible – and 100 percent unnecessary. No one can be good enough or make himself feel bad enough, to earn his way into heaven. But no one has to, because Jesus paid the full price of entry on behalf of all true Christians.
From Hard to Believe – copyright 2003 by John MacArthur (Published by Thomas Nelson – Nashville, TN), p.145