“A glad heart makes a happy face” Proverb 15:13
I’m not aware of any Biblical mandate to smile, but the Bible does have a lot to say about “joy” and a smile is the natural bi-product of joy. Let’s face it, (no pun intended) a smile improves any face and brightens any place; and it has a way of perpetuating itself, it’s contagious… like a yawn, when someone else does it others are prone to do likewise. When your coffee isn’t hot, try smiling. When you miss the bus, try smiling. When you’re stuck in traffic, try smiling. It doesn’t change things but it can’t make them worse. So in preparation for worship this Sunday practice smiling, then bring your smile with you and share it with others.