Luke 15: 3-7  NAS

So He told them this parable, saying,  "What man among you, if he has a hundred sheep and has lost one of them, does not leave the ninety-nine in the open pasture and go after the one which is lost until he finds it?  When he has found it, he lays it on his shoulders, rejoicing.  And when he comes home, he calls together his friends and his neighbors, saying to them, 'Rejoice with me, for I have found my sheep which was lost!'  I tell you that in the same way, there will be more joy in heaven over one sinner who repents then over the ninety-nine righteous persons who need no repentance."