Mattityahu 6:21-24

For where your otzar is, there also will be your lev. The eye is the menorah of the basar. Therefore, if your eye is unblurred, then your whole basar will be lighted. But if yours is the ayin horo, your kol is choshech; if ohr choshech, great choshech! No one is able to serve two adonim (masters). For either he will have sinah (hatred) for the one and ahavah (love) for the other, or he will be devoted to the one and despise the other. You cannot serve HASHEM and Mammon (Money).