Romans 14:1 says "Accept him whose faith is weak, without passing judgment on disputable matters." Note carefully the phrase, "disputable matters" - it is key to understanding what Paul is really talking about.
Disputable matters are just that - matters that can be argued or debated or disputed. These are things which arise out of man made tradition, borne out of man's opinions and leanings and not God's commandments. That is vital to understand.
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