Here's a clean joke.
A young boy had just gotten his driver's license and inquired of his father, if they could discuss his use of the car. His father said he'd make a deal with his son. "You bring your grades up from a C to a B average, study your Bible a little, get your hair cut and we'll talk about the car."
The boy thought about that for a moment, decided he'd settle for the offer and they agreed on it.
After about six weeks his father said, "Son, I've been real proud. You brought your grades up and I've observed that you have been studying your Bible, but I'm real disappointed you haven't gotten your hair cut."
The young man paused a moment then said, "You know, Dad, I've been thinking about that, and I've noticed in my studies of the Bible that Samson had long hair, John the Baptist had long hair, Moses had long hair and there's even a strong argument that Jesus had long hair."
To this his father replied, "Did you also notice they all walked everywhere they went?"