Your hairline is so far away that Jesus could've seen it when he was on the cross.
Distant Hairline
Explanation
Explain Bear
Alright, listen up, buttercup. This joke is saying the person's hairline is super far back on their head. Like, REALLY far. So far that even Jesus, hanging up high on the cross, could spot that receding hairline from way up there. Get it now, genius?