Romans 14:22

Hast thou faith? — It is with some reluctance that in deference to the union of the four best MSS. we give up the Received text here, and substitute (by the insertion of the relative) “The faith which thou hast, have to thyself before God,” i.e., reserve the exhibition of it to the privacy of your own direct communion with God, and do not display it ostentatiously in public where it may do harm. “It is indeed” — the Apostle continues — “a happy thing to have no self-condemnatory scruples of conscience, but, on the other hand, it is fatal to have scruples and to disregard them.”

In that thing which he alloweth. — In the acts which he permits himself. He is a happy man who can eat what he pleases, and drink what he pleases, without any qualms of conscience to condemn him while he does so.