Roma 14:14

14:14 I know and am convinced in the Lord Jesus that there is nothing unclean in itself; still, it is unclean to the one who considers it unclean.

Roma 14:20

14:20 Do not destroy the work of God for the sake of food. For although all things are clean, ¹  it is wrong to cause anyone to stumble by what you eat.

Roma 15:1

Exhortation for the Strong to Help the Weak

15:1 But we who are strong ought to bear with the failings of the weak, and not just please ourselves. ² 

[14:20]  ¹ sn Here clean refers to food being ceremonially clean.

[15:1]  ² tn Grk “and not please ourselves.” NT Greek negatives used in contrast like this are often not absolute, but relative: “not so much one as the other.”