Romans 6:19

6:19 (I am speaking in human terms because of the weakness of your flesh.) For just as you once presented your members as slaves to impurity and lawlessness leading to more lawlessness, so now present your members as slaves to righteousness leading to sanctification.

Romans 14:6

14:6 The one who observes the day does it for the Lord. The one who eats, eats for the Lord because he gives thanks to God, and the one who abstains from eating abstains for the Lord, and he gives thanks to God.