The original 13 rules of basketball, as drafted by James Naismith

Canadian Dr. James Naismith created the game of basketball from 13 original rules. Because Naismith wanted a non-violent game that could be played inside, the first seven rules consist of set guidelines for play, with scoring not even mentioned until the eighth rule. 

Though the rules have been modified over time, the essential principles remain constant.

The ball may be batted in any direction with one or both hands.
Current: The ball can still be batted away with one or both hands. It can be batted from a player’s hands or batted away during a shot. This rule led to the evolution of the blocked shot, as defensive players can block a shot while it is on its upward path to the basket.

A player cannot run with the ball, as he must throw it from the spot on which he catches it, with allowance to be made for a man who catches the ball when running at a good speed.

Current: A player cannot run with the ball, as he must dribble or pass the ball. A player running with the ball is called for travelling.

The ball must be held in or between the hands; the arms or the body must not be used for holding it.
Current: The ball can only be held in the hands or the arms of a player. A player cannot use his body to hold the ball or to obstruct the ball from getting to a player or going in the net.

No shouldering, holding, pushing, tripping or striking in any way the person of an opponent shall be allowed. The first infringement of this rule by any person shall count as a foul, the second shall disqualify him until the next goal is made, or if there was evident intent to injure the person, for the whole of the game, no substitute allowed.

Current: The noted offences still apply today and result in fouls or even ejections. Like the Naismith rule, a player can be thrown out of a game for intent to injure. A flagrant foul is unnecessary or excessive contact against an opponent that results in two shots and possession of the ball. A player that commits a flagrant foul may be ejected from the game or suspended for a period of time.