In everything you do this will sustain you. If you’re teaching Sunday school, and it's a tough day, and it's a difficult class, and you've got some problems, this will see you through. Do it as an act of love for the Lord. You are making him known. Yes, its love for the children too, but pre-eminently this is how you have to think: it is for the Lord. When we preach, we must do it for him, to make him known, out of our own indebtedness to him. That must be the motivation, the driving force, the energy of everything we do. We do it for him. If it's not done for him, how can it be blessed? Mary set us an example.