Lay down this rule of friendship: neither ask nor consent to do what is wrong. The plea, 'for friendship's sake,' is a discreditable one, and should not be admitted for a moment. We should ask from friends and do for friends only what is good.
Any man may make a mistake; none but a fool will stick to it. Second thoughts are best as the proverb says.
[Lat., Cujusvis hominis est errare; nullius, nisi insipientis, in errore perseverae. Posteriores enim cogitationes (ut aiunt) sapientiores solent esse.]