Mommy told me something a little kid should know It's all about the devil and I learned to hate him so She said he causes trouble when you let him in your room He'll never ever leave you if your heart is filled with gloom So let the sun shine in, face it with a grin Smilers never lose and frowners never win So let the sun shine in, face it with a grin Open up your heart and let the sun shine in When you are unhappy, the devil wears a grin But oh, he starts to run in when the light comes prowling in I know he'll be unhappy 'cause I'll never wear a frown Maybe if we keep on smiling he'll get tired of hanging 'round If I forget to say my prayers the devil jumps with glee But he feels so awful, awful when he sees me on my knees So if you feel of trouble and you never seem to move Just open up your heart and let the sun shine in So let the sun shine in, face it with a grin Smilers never lose and frowners never win So let the sun shine in, face it with a grin Open up your heart and let the sun shine in Sun shine in, sun shine in Mommy told me something a little kid should know It's all about the devil and I learned to hate him so If I forget to say my prayers, the devil jumps with glee But he feels so awful, awful when he sees me on my knees So if you feel of trouble and you never seem to move Just open up your heart and let the sun shine in