"Their heart is divided; Now they are held guilty. He will break down their altars; He will ruin their sacred pillars." (Hosea 10:2; NKJV)
Jehovah would have us love Him with a single heart. Their can be no divided loyalties. We must love Him and Him alone in order to glorify Him and Him alone.
"No one can serve two masters; for either he will hate the one and love the other, or else he will be loyal to the one and despise the other. You cannot serve God and mammon." (Matthew 6:24; NKJV)