Okay kiddo, so you know how sometimes people get sick? Well, a long time ago in Jerusalem, there was a special place called the Pool of Bethesda where people who were sick would go to try and get better.
The pool had five porches, which were like covered areas where people could sit and wait to get into the water. They believed that when the water in the pool stirred, an angel was touching the water and whoever got in first would be healed.
But the thing is, not everyone could get into the pool fast enough because there were a lot of people who were sick and waiting. There was a man who had been sick for 38 years and had been trying to get into the pool for a long time but never made it in time.
One day, a man named Jesus saw the sick man and asked him if he wanted to be healed. The sick man said yes, but he didn't have anyone to help him into the pool. Jesus then told him to get up, pick up his mat and walk - and the man was healed!
So, the Pool of Bethesda is a place where people went to try and get better a long time ago, and it's also where Jesus helped a man who had been sick for a very long time.