Quote - John MacArthur

"If we are truly born of God, we have a faith that cannot fail to overcome the world (1 John 5:4).  We may sin (1 John 2:1) - we will sin- but the process of sanctification can never stall completely.  God is at work in us (Phil. 2:13), and He will continue to perfect us until the day of Christ (Phil 1:6; 1 Thess. 5:23-24)."  The Gospel According to Jesus by John MacArthur (p. 33)