Luke 14:34

Salt is good, but if the salt have lost his savour, &c. Salt is good as long as it retains its peculiar properties. So also ye who are my Apostles, as long as ye preserve your spiritual powers, will be useful to the world to season it with the salt of gospel faith and wisdom. But if ye lose your savour, ye will be good for nothing but to be despised and trodden under feet of men, for there is no one to season or correct you. Bede. See also Comment. on S. Matthew 5:13, and S. Mark 9:50.

This parable applies not only to the Apostles, but in a measure to all Christians. For they ought, by the innocence of their lives and their good example, to season unbelievers who are, as it were, unsalted.