Jesus was talking to the Pharisees. They thought they were better than everyone else, better than the tax collectors and the other sinners that Jesus talked to and spent time with. They couldn’t understand why Jesus spoke to them and had meals with them.
Jesus told them two parables. The first one was about a shepherd who had a herd of 100 sheep. One day he realised one of his sheep was missing. He loved his sheep very much so he set off to find his lost sheep. He searched over hills and mountains until he found his missing sheep, picked it up and brought it back home. He celebrated with his friends and neighbours because he had found the sheep which was lost.
In the second parable a lady had lost one of her ten silver pieces. She searched all over her house, swept the floor and looked in all the pots until she found the silver piece that was missing. The silver piece was so precious to her that when she found it she had a big celebration with all her friends.
Jesus told the Pharisees that there is great rejoicing in heaven over one sinner who repents of their sins and trusts in God.