There are sincere Christians who strongly believe in man-made rules, insisting that we need these rules in order to know how to live holy lives. Yet Colossians 2:20-23, clearly states that these rules will not make you holy.
In John 17:17, Jesus prayed "Sanctify them through your truth. Your word is truth." The passage could also be correctly translated "Separate them through your truth," or "Make them holy through your truth."
Now we see that God's Word (which does not contain man-made rules) does make you holy. The next question is "How?"