Which woman, if she has ten coins and loses one, does not light the lamp and sweeps the house and searches carefully until she finds it? And after finding it, she calls her friends and neighbors, saying: Rejoice with me, because I have found the coin I had lost. So, I tell you, there is joy before the angels of God for a single sinner who is converted".
The Gospel according to Luke places this parable between that of the lost sheep and that of the prodigal son; all three are inserted in the context of the confrontation between Jesus on one side and the Pharisees and Doctors of the law on the other, who murmured because He welcomed sinners and ate with them, that is, he did not drive them away and did not marginalize them as instead Pharisees and Doctors they did and imposed to do, but shared with them even the most convivial moments like meals; in a single word he allowed them, who more than once had praised for morally more correct behaviors than those of the same masters of the temple, to listen to him and be "readmitted" to the community.
Jesus is talking about himself and his mission to people who in the Jewish community were kept at a safe distance because they were considered to be far from the law (tax collectors, sinners, prostitutes, etc.). These people therefore never had the opportunity to confront themselves with a "rabbi" on religious subjects; Jesus, on the other hand, is not only available for comparison, but shares his table with them.
The proud Pharisees could not understand how Jesus could show himself so full of benevolence towards them. The teaching that Jesus wants to express with this parable is addressed directly to them and to their personal experience, demonstrating the groundlessness of their murmurs. The parable of the lost drama is conceived with the same purpose as the previous one, that is, to demonstrate the joy that comes from uniting the animal (sheep), the object (drama) or the person (prodigal son) who has separated - more or less voluntarily - from the whole, from the community, from the whole to which it must instead remain tied, so that its being one has a meaning through its sense of belonging to that whole.
For the woman in the parable, the ten coins represent a precious whole, they are her treasure: to have lost even one of them was therefore a great harm to her, and this explains why she is so busy to find it. And how do you find it, to bring it back into that whole to which it belongs? He lights the lamp and sweeps the house, that is, he brings the light back to where before there was "darkness" and sweeps, cleans, drives away "dirt" from his home: he already seems to see Jesus in action when, "entered the temple, he began to hunt those who did business, telling them "My house will be a house of prayer. You, on the other hand, have made it a cave of thieves!".
The Pharisees and the scribes felt offended, because Jesus had asked them to think like a shepherd, in the parable preceding this one, and invited them now to imagine themselves as a woman, an even greater insult: the shepherds were considered unclean and women worthy of little consideration and even less of respect. A drama or drachma was a Greek silver coin roughly equivalent to a denarius, the Roman coin corresponding to a daily payday for an unskilled worker.
This woman sets to work to "bring her back to the light" and does not stop until she realizes this goal by reuniting her with the other nine, because it is precious, it has enormous value for her who has only ten coins. That is why, when she finds it and rejoins the others; she also calls his friends and neighbors to enter her home, to rejoice in her treasure, which is now complete again: "Thus, I say to you, there is joy before the angels of God for a single sinner who repents".
The great joy concludes this parable, just as the parable of the lost and found sheep concluded with it; and Jesus goes further, comparing this joy as that which occurs in heaven when a lost soul is saved. The parable is even more surprising, and scandalous for the Pharisees and Doctors of the law, because moreover it presents a woman as a metaphor for the saving work of God, something that does not happen in any other parable.
How could the Pharisees and the scribes understand the joy of a humble woman of an insignificant village, tried for the discovery of something of little importance to them? How could they even imagine the joy of God in heaven for the eternal salvation of a sinner? This is why the emphasis of the parable falls on the heavenly joy for the repentance of a sinner, this is why Jesus does not reject sinners, but lets them approach him, talk to them, eat with them, share his joy with them by expressing the celebration in advance divine that it will be up to the sinner who repents.
Heaven gets excited when a sinner is found! It is a glorious day in which a lost person is saved by the grace of the Lord God: the angels, Jesus, God Himself rejoice because the sinner was forever torn from the slavery of sin and the devil!