Romans 14:5 - Matthew Poole's English Annotations on the Holy Bible

One man esteemeth one day above another: another esteemeth every day alike: there were differences in the church of Rome about the observation of days, as well as the choice of meats; and in this he endeavours an accommodation as well as in the other. The converted Jew was of opinion, that the festival days appointed in Moses's law, were holier than other days, and that they should still be observed: see Galatians 4:10 Colossians 2:16. On the other side, the believing Gentile was of opinion, that the difference in days under the Old Testament was now ceased, and he (the text says) esteemed or approved of all days. The word alike is not in the original, but it is aptly supplied by our translators. Let every man be fully persuaded in his own mind; i.e. Let every man be satisfied as to the grounds of his practice; let him act by his own and not another man s, judgment and conscience; let him be so fully assured in his own mind of the lawfulness of what he doth, as to find no doubting or scrupulous hesitations in the doing of it; let him be able to say as the apostle himself doth, Romans 14:14. The reason of this counsel you have, Romans 14:23. He that doth what he thinks is a sin, is an offender against God, whether it be a sin or no. And yet a man may sin in that wherein he is fully persuaded he sinneth not. A full persuasion must be had, but it is not sufficient to make an action good or lawful.