According to "How I Met Your Mother," you need to wait three days before calling a girl -- and that this is a rule handed down from Jesus. The theory was well thought out... if Jesus had only been dead one day, some people might not know it. And I'm paraphrasing here, but he might go up to someone and they're like
"Yo, Jesus. What up?"
"I was dead."
"I died. But I came back to live."
"Yeah, whatever, dude."
And one day would be Saturday and everyone's busy. But by waiting until Sunday, everyone's already in church, so everyone's sitting there and they're kinda sad. And he busts in from the back of the church and cheers everyone up because he's alive again.
And that, according to Barney, is why you must wait three days to call a girl.