Willful repudiation is different from falling into sin from what I can see.
It is different, but again, saving/justifying faith is in the Lord Jesus, and thus a believer repents when convicted of sin (not ignorant of it), which I must do often, and resisting that is presuming upon God's (who is patient) grace. "Wherefore (as the Holy Ghost saith, To day if ye will hear his voice, Harden not your hearts, as in the provocation, in the day of temptation in the wilderness" (Hebrews 3:7-8) and died outside the promised land.
Thus, while Jesus comforted the afflicted, he afflicted the complacent. A false concept of faith fosters the latter.