Alt Text: Panel 1: Three disciples and Jesus stand outside a closed tavern at night. One disciple says, “Oh man, the tavern’s closed.” Panel 2: The other disciple sighs and says, “Aww, too bad. I was really in the mood for a drink.” Jesus looks thoughtful. Panel 3: The disciples watch Jesus expectantly. Panel 4: Jesus puts on a blood-drawing cuff and prepares to prick his arm with a needle, saying, “Sigh… Fine.”
That is his thing, but the joke here is that his blood is also often represented as wine / grape juice. The unexpectedness of it is where the humor of this specific strip comes from.
Now I’m the one being taken too seriously. I was just saying, I already got the joke and everything. Didn’t mean to bait anyone.