it goes:

A young jewish boy and his arab neighbor, living in Israel, grew up together, spent every day with each other, laughing and playing. They both went to their respective temple/mosque for religious services, and both decided to dedicate their lives to serving God.

For their entire adult lives, they would meet and play chess together, always trying to convince the other about who was right about Yaweh/Allah. Finally, one day, during their game of chess, both men died.

When they opened their eyes, they were both standing in front of the pearly gates, and an angel welcomed them both into their Father's home. As they stepped through, the angel asked them to be very quiet as they walked down the hallway to the Jewish and Muslim Heavens.

"Why do we have to be quiet, we're in Heaven!" one asked.

The angel replied "Because those first few doors are for each of the Christian sects' heaven, and they all think they're the only ones up here!"