Romans 14:1-6

As for the one whose faith is weak, accept him [into your fellowship], but not for [the purpose of] quarreling over his opinions. One man’s faith permits him to eat everything, while the weak believer eats only vegetables [to avoid eating ritually unclean meat or something previously considered unclean]. The one who eats [everything] is not to look down on the one who does not eat, and the one who does not eat must not criticize or pass judgment on the one who eats [everything], for God has accepted him. Who are you to judge the servant of another? Before his own master he stands [approved] or falls [out of favor]. And he [who serves the Master—the Lord] will stand, for the Lord is able to make him stand. One person regards one day as better [or more important] than another, while another regards every day [the same as any other]. Let everyone be fully convinced (assured, satisfied) in his own mind. He who observes the day, observes it for the Lord. He who eats, eats for the Lord, since he gives thanks to God; while he who abstains, abstains for the Lord and gives thanks to God.