In Luke 15 Jesus told three lost-and-found parables in response to complaints from the Pharisees and scribes that He consorts with sinners even to the extent of eating with them. To the Jews tax collectors were turncoats and, consequently, the worst kind of sinners because they worked for the Roman government to extract taxes from their Jewish brothers.
In the parable of the lost sheep the owner leaves the flock behind to search for one sheep that has become separated from the flock. In the parable of the lost coin a woman loses one of her ten silver coins and searches her house until she finds it. Both the sheep owner and the woman report the good news to friends and neighbors so they can share in the joy of their search and recovery efforts!