Have you had a sporting event or party or anything that was super important to you take place the day before a huge test? And you had to make the awful decision of going to the super important event or studying for your test? Let’s just say you chose that super important event (not like YOU would ever do anything like that… right?) and told your parents (and maybe even yourself) that you were totally prepared for the test, so it was ok. Well… how well did you do on that test? Probably not great.
It’s impossible to serve two masters. In this case, it’s impossible to do that thing you really want to do AND properly prepare for your test. Our relationship with God is no different. He demands our attention, and we NEED Him. Sometimes, we can get distracted by other things that seem super important… but we can’t afford to fail in our relationship with Him.