What does my sin say about my faith? It can be pretty ugly! But let’s be realistic; no matter how good we ultimately become we’ll always have shortcomings. Still, we must not be naïve about the influence sin has on our life—that is, how it affects both faith and obedience. Sin weakens our ability to make right choices. It hardens us. Like a snowball—growing in size and gaining momentum—sin and unbelief feed on each other, sometimes even leading to total alienation from God.
To prevent this from happening, we must guard our heart—even from sins that may seem insignificant. At the very least, disobedience stalls our growth. At worst, it hardens our heart to the point where we simply cease to believe. Sure, we’ll never be perfect in this life. But walking in Christ’s provision is what’s really important. God loves watching us work out our faith this way.
From Free from the Power of Sin: the Keys to Growing in God in Spite of Yourself