Season 4: Episode 87: Prodigal Son
Everyone gets on Ray's case because he's doesn't go to Sunday Mass. When Ray starts feeling guilty about the good example Frank is setting by attending church, he commits to becoming a regular parishioner. After all, if Frank can do it, so can he. But, when Ray shows up at the church, he quickly realizes what it is that draws Frank to this house of worship week after week--and it isn't the sermon.