John Calvin's Commentary on the Bible - Romans 14:6
Verse 6 6.He who regards a day, etc. Since Paul well knew that a respect for days proceeded from ignorance of Christ, it is not probable that such a corruption was altogether defended by him; and yet his words seem to imply, that he who regarded days committed no sin; for nothing but good can be accepted by God. Hence, that you may understand his purpose, it is necessary to distinguish between the notion, which any one may have entertained as to the observance of days, and the observance itself... read more
John Calvin's Commentary on the Bible - Romans 14:5
Verse 5 5.One indeed, etc. He had spoken before of scruples in the choice of meats; he now adds another example of difference, that is, as to days; and both these arose from Judaism. For as the Lord in his law made a difference between meats and pronounced some to be unclean, the use of which he prohibited, and as he had also appointed festal and solemn days and commanded them to be observed, the Jews, who had been brought up from their childhood in the doctrine of the law, would not lay aside... read more