Play a guessing game with your class. It could be a game such as finding two words that begin with a, b, c and so on. Before starting the game point out the need to have rules. These could include:
Who goes first?
If you guess a word, do you get another turn?
Who will keep score?
How many points for each correct answer?
After the game, point out how hard it would be to play a game without rules. Connect this to the Ten Commandments. God gave us rules, or commandments, to help us know the right way to live. It would be hard to make good choices without rules to tell us right from wrong.