One of my favorite songs of all time and one of the easier songs for me to sing is Amzing Grace. But if you don't know a song I wouldn't suggest you try to sing it, with a room full of people. Lip synching, or mumbling  won't help you either. Even if he is singing for God this isnt a good look.

If  I didn't know a song, I remember as a kid singing in the church choir lip synching "watermelon", but this guy takes it to a whole another level. Then he tells the whole church to join along. He really does sound like a combination of Jesus and Fergie. At the end it gets even funnier when he starts really getting into it and hits all those high notes. Can the congregation say 'Amen', and 'Sexual Chocolate'.