ДВУМ ГОСПОДАМ НЕ СЛУЖАТ

Cf:Between two stools one falls (goes) to the ground (Br.). Between two stools we come to the ground (Am.). Don't embark on two boats, for you'll be split and thrown on your back (Am.). Don't run with the hound and hold on to the hare (Am.). If you try to sit on two chairs, you'll sit on the floor (Am.). No man can serve two masters (Am.,Br.). You cannot run with the hare and hunt with the hounds (Br.)