John Calvin on 1 Corinthians 10:15

15. I speak as to wise men. As he was about to take his argument from the mystery of the Supper, he arouses them by this little preface, that they may consider more attentively the magnitude of the thing. “L’excellence de ce mystere;” — “The excellence of this mystery.” “I do not address mere novices. You understand the efficacy of the sacred Supper in it we are ingrafted into the Lord’s body. How unseemly a thing is it then, that you should enter into fellowship with the wicked, so as to be united in one body. At the same time, he tacitly reproves their want of consideration in this respect, that, while accurately instructed in the school of Christ, they allowed themselves in gross vice, as to which there was no difficulty in forming an opinion.