[for me anyway] we may understand v34. by understanding the word "committeth" which putting trust into the hands and power of; which is exactly why Christ refers to them that puts their trust into the hands of sin are the servants of sin: contrariwise they that are born of God do not put their trust into the hands and power of sin (1 John 3:9).
It's about whom
you obey, to whom you obey you become
a servant to and are marked by the spirit of your master, by
sin, or by
righteousness...
Romans 6:16
Know ye not, that to whom ye
yield yourselves servants to obey,
his servants ye are to whom ye
obey; whether of
sin unto
death, or of
obedience unto righteousness?
Sin
reigning in ones life(sin having dominion over) and one receiving the
red mark of the beast (sin nature) was shown in Cain....
Genesis 4:7
If thou
doest well, shalt thou not be accepted? and if thou doest
not well,
sin lieth at the door. And unto thee shall be his
desire, and thou shalt
rule over him.
So when Cain did not do good
sin became his
desire (same as the
Devils desire) by the
spirit of the Devil working
in him, and thus he became a
servant of sin with
sin reigning over him unto death. Also because of Cain sinning he was cast out of the presence of God (as sin separates us from God) and Cain was
marked with the mark of the beast (serpents desire and sinful nature).