The passage
      v9. Matthew is at the customs and excise booth on the border between the territories of Philip and Herod Antipas, situated on the outskirts of Capernaum. In 9:1-8 we see Jesus as the one with authority to forgive sins. Jesus now uses his authority to appoint a sinner to his apostolic band. Matthew, also called Levi, is recorded as an apostle in both Mark and Luke. It is not uncommon to have two interchangeable names. Tradition tells us that Matthew is the author of this gospel, although it is more likely only attributed to him. If the passage does record the call of the author, it is very self effacing, since Luke tells us that Matthew "left everything" and followed Jesus.
      v10-11. Although both Mark and Luke specify the house as Matthew's, the text here does not specifically identify whose house it is (even though the NIV does). As far as the Pharisees are concerned, Jesus and his disciples are in danger of ritual defilement by eating with "sinners". "Sinners" are evil-livers such as tax collectors, harlots and the like, but also the "common folk" whose lives do not allow them to maintain the Pharisaic Halakoth (rules of conduct - washing, food.....). The Pharisees obviously bail up some of the disciples outside the house. Their question to the disciples is not really a question, but rather a charge of wrong-doing.
      v12. Jesus overhears the charge and gives the Pharisees something to think about. Just as the sick need a doctor, so the sinful need mercy and forgiveness. As Jesus has healed the sick, so he happily forgives the sinner. In fact, it is for this very reason that Jesus has come, 1:21. The Pharisees don't quite understand this approach. They expect the messiah to overthrow the Roman authorities and reestablish the purity of Judaism. Sadly it is the Pharisees who are sick. Jesus bypasses these "righteous" hypocrites and goes straight to the "sinners". The difference between the "healthy" ("righteous") and the "sick" ("sinners") is certainly not sin. Both the "righteous" and "sick" are sinners. Jesus goes to the sick, not just because they are sick, but because they know they are sick and want to get well. Why else would evil-livers come to hear a wandering teacher? The gospel is for the "lost" who want to be found.
      v13. Jesus now quotes Hosea 6:6 and tells the Pharisees to "go and learn" what it means. Hosea denounced a formal ritualistic temple worship which had lost its substance; lost its "mercy" (hesed), its "covenant love." Jesus' point is that the Pharisees have preserved the shell, but lost the substance. They are like the apostate religious community of Hosea's day and their attitude toward "sinners" demonstrates this loss. It is not their lack of sympathy for outcasts that condemns them, but their failure to apply mercy and forgiveness and so include outcasts in the community of grace. It is for this very reason that Jesus sets out "to invite" (better than "to call") "sinners" into the kingdom. Jesus' task is to reconcile the "lost" to God - those separated from God, but who want to know God. The "righteous", who need no "doctor", think that they are in the kingdom because of their righteousness, yet this assumption leaves them beyond help because they fail to recognize their state of loss. They are self-righteous and therefore lost.

I desire mercy
      It is interesting how Jesus' words often prompt the very response they denounce. This may just evidence the human condition, or may even enact the saying, "I have come that those who see may not see."
      The social gospel is alive a well today such that "justice" is often proclaimed as the nub of the gospel. So, sympathy for the outcast is the "mercy" required by God. Accessing "sinners" into the church, in the sense of accessing social deviates, down-and-outs ....., is affirmed against the desire to access the "righteous", namely, nice healthy successful middle-class people.
      For Jesus, the business of accessing has nothing to do with social standing, but has everything to do with a person's standing before God. The human tribe can be divided into three groups. There are those who, as in the animal kingdom, breath, bathe, breed..... without the slightest thought about "eternal verities." Then there are those who are into "eternal verities." There are the "righteous", those who believe they have built their house on the rock, but are actually on the sand. Then there are the "sinners, those who know they have built their house on the sand and are looking around for someone to get them on the rock. It's to the sick sandy crew that Jesus comes, the lost who want to be found.

v10
      aJmartwloi "sinners" - It may be referring to those who do not observe the ritual law, but given the context it is more likely referring to "evil livers." Most tax collectors were thieves and their friends were probably worse. So, here was a corrupt crowd, but they freely came to hear Jesus. His message to them was that "salvation is for people just like you." "non-observant [Jews]", Anchor; "people with whom no respectable Jew would have had anything to do", Barclay.

v12
      oiJ iscuonteV (iscuw) pres. act. part. "the healthy" - the ones being healthy / strong. Participle as a substantive. "People who are well", TEV. oJi kakws exontes "the sick" - the ones having sickness / illness. "Those who have it bad."