A man with two employers cannot be faithful to both. Nor can a man support two
conflicting causes. The source is Matthew, vi, 24: ‘No man can serve two
masters; for either he will hate the one and love the other; or else he will
hold to the one, and despite the other. Ye cannot serve God and mammon.’

##### See also:

* A door must be either shut or open
* You cannot burn the candle at both ends
* You cannot have it both ways
* You cannot have your cake and eat it
* You cannot run with the hare and hunt with the hounds
* You cannot sell the cow and drink the milk