The Prescription Against Heretics by Tertullian
Chapter XI.--After We Have Believed, Search Should Cease; Otherwise It Must End in a Denial of What We Have Believed. No Other Object Proposed for Our Faith.
There is impunity in erring, if there is no delinquency; although indeed to err it is itself an act of delinquency. With impunity, I repeat, does a man ramble, when he (purposely) deserts nothing. But yet, if I have believed what I was bound to believe, and then afterwards think that there is something new to be sought after, I of course expect that there is something else to be found, although I should by no means entertain such expectation, unless it were because I either had not believed, although I apparently had become a believer, or else have ceased to believe. If I thus desert my faith, I am found to be a denier thereof. Once for all I would say, No man seeks, except him who either never possessed, or else has lost (what he sought). The old woman (in the Gospel) had lost one of her ten pieces of silver, and therefore she sought it; when, however, she found it, she ceased to look for it. The neighbour was without bread, and therefore he knocked; but as soon as the door was opened to him, and he received the bread, he discontinued knocking. The widow kept asking to be heard by the judge, because she was not admitted; but when her suit was heard, thenceforth she was silent. So that there is a limit both to seeking, and to knocking, and to asking. |For to every one that asketh,| says He, |it shall be given, and to him that knocketh it shall be opened, and by him that seeketh it shall be found.| Away with the man who is ever seeking because he never finds; for he seeks there where nothing can be found. Away with him who is always knocking because it will never be opened to him; for he knocks where there is none (to open). Away with him who is always asking because he will never be heard; for he asks of one who does not hear.