Adam Clarke on Romans 14:20

For meat destroy not the work of God - Do not hinder the progress of the Gospel either in your own souls or in those of others, by contending about lawful or unlawful meats. And do not destroy the soul of thy Christian brother, Rom 14:15, by offending him so as to induce him to apostatize.

All things indeed are pure - This is a repetition of the sentiment delivered, Rom 14:14, in different words. Nothing that is proper for aliment is unlawful to be eaten; but it is evil for that man who eateth with offense - the man who either eats contrary to his own conscience, or so as to grieve and stumble another, does an evil act; and however lawful the thing may be in itself, his conduct does not please God.