You get this sidequest after talking to Priest Maxi near Town Hall. He'll tell you to find Jesus, but you only have to do this literally. Just go into the church and Jesus is hiding behind one of the pews. Go back to Maxi and he'll tell you to find Jesus again. Go back to the church and head to the back. Move the lights near the podium and switch off the lights near the right door and you can see Jesus. Go behind the podium and interact to get Jesus and you can then use Jesus as your summon, which you can use once a day.