
Hilary of Poitiers
Catena Aurea · Matthäusevangelium 5
Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men.
And because man is ever liable to change, He therefore warns the Apostles, who have been entitled the salt of the earth, to continue stedfast in the might of the power committed to them, when He adds, If the salt have lost its savour, wherewith shall it be salted?