No man can serve two masters

One's loyalties must be undivided. This is a saying of Jesus from the Gospels. Jesus goes on to say, “You cannot serve God and mammon” — that is, God and money.

A saying of Jesus. The complete passage reads, “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 despise the other.”