87.  That believers ought to be simple, with prudence. In the Gospel according to Matthew:  “Be ye prudent as serpents, and simple as doves.” 4561 And again: “Ye are the salt of the earth. But if the salt have lost his savour, in what shall it be salted? It is good for nothing, but to be cast out abroad, and to be trodden under foot of men.” 4562 4561     Matt. x. 16 . 4562     Matt. v. 13 .