Knowing God by: His Love

 "Teach these new disciples to obey all the commands I have given you. And be sure of this: I am with you always, even to the end of age."
Matthew 28:20

It would be awesome if people you love could promise that they will never, ever leave you. They can't, all humans will die eventually. Not much we can do about that. Beyond that, sometime friends stop being friends. Sometimes families break up and one parent leaves (even though their love for you never stops). Sometimes when the going gets tough, people leave.
One way that you know God totally loves you is that He will never, ever leave you. Never. He promises. Gods love is incredibly strong and He will stay with you no matter how tough life gets, regardless rather or not you love him back.
He wants you to obey him and do his work, of course. But even if times happen when you don't want them to... He will never leave you.