Satan and the old man

Church was in full swing... Pews were packed. Suddenly, Satan appeared at the front of the church. Everyone started screaming and running for the front entrance, trampling each other in a frantic effort to get away from the evil incarnate.
Soon everyone had left the church except for one elderly gentleman who sat calmly in his pew without moving, seeming oblivious to the fact that God's ultimate enemy was in his presence.
So Satan walked up to the old man and said, "Don't you know who I am?"
The man replied, "Yep, sure do."
"Aren't you afraid of me?" Satan asked.
"Nope, sure ain't." said the man.
"Don't you realize I can kill you with a word?" asked Satan.
"Don't doubt it for a minute," returned the old man, in an even tone.
"Did you know that I could cause you profound, horrifying, AGONY for all eternity?" persisted Satan.
"Yep," was the calm reply.
"And you're still not afraid?" asked Satan.
"Nope," said the old man.
More than a little perturbed, Satan asked, "Well, why aren't you afraid of me?"
The man calmly replied, "Been married to your sister for 48 years."