Bad company is like a nail driven into a post, which, after the first and second blow, may be drawn out with little difficulty; but being once driven up to the head, the pincers cannot take hold to draw it out, but which can only be done by the destruction of the wood.
Saint AugustineWhat difference, if you are mistaken? For if I am mistaken, I am. For he who is not, assuredly cannot be mistaken; and therefore I am, if I am mistaken. Therefore because I am if I am mistaken, how am I mistaken that I am, when it is sure that I am, if I am mistaken.
Saint Augustine