Soaking beans prior to cooking the beans helps to remove the gas from the beans and also helps the beans cook faster.
However you do not have to soak the beans before cooking them and they will cook just fine but if you don't soak the beans before cooking the beans they will give you gas in your stomach and also take about 1 hour to 2 hours longer to cook.
If you want to remove the gas from the beans so that you don't get so much gas in your stomach and fart so much from the beans then soak them prior to cooking them.
But you can just cook beans either in a pot on the stove or in a slow cooker and they will cook just fine.
I prefer to cook beans in a slow cooker so that I can cook them while I'm away at work or sleeping and they will be ready to eat and serve the next day.