Just for the hell of it I thought I'd throw in this translation of Caxton's, which dates back to 1484. So ignore the expiration dates of English and follow me into the bloody maw of wisdom!
1.10. Of the man and of the serpent
He that leneth and helpeth the euylle men / synneth / for after that men haue doo to them some good / they hurte them afterward / For as men sayen comynly / yf ye kepe a man fro the galhows / he shalle neuer loue yow after / wherof Esope reherceth suche a fable / A man was somtyme / whiche fond a serpent within a vyne / and for the grete wynter and frost the serpent was hard / and almost dede for cold wherof the good man had pyte and toke and bare her in to his hows and leyd her before the fyre / and so moche he dyd that she came ageyne in to her strengthe and vygour / She beganne thenne to crye and whystled about the hows and troubled the good wyf / and the children / wherfor this good man wold haue her oute of his hows / And whanne he thoughte to haue take her she sprange after his neck for to haue strangled hym /
And thus hit is of the euyll folk whiche for the good done to them / they yeld ageyne euyll and deceyuen them whiche haue had pyte on them / And also theyre felauship is not good ne vtyle /
Let that be a life-saving lesson to you! Memorize it.