Many believe St. Matthew, the tax collector in today's passage, is also the author of the Gospel of Matthew, but many scholars hold this improbable and date the Gospel forty to sixty years after the death of Jesus.
In Matthew 9.9 we have the calling of Matthew; Jesus takes the tax collector as a disciple and eats dinner at his house with other tax collectors and "sinners." When he is questioned by the Pharisees about the company he keeps, Jesus says, "For I have come to call not the righteous but sinners" (Mt. 9.13). Jesus is always siding with the underdogs, those who are marginalized and the oppressed, and even shows them blatant favoritism at time to other social groups. Although Jesus' teachings and sacrifice is for all people, his ministry certainly focuses on and favors the poor, needy and outcast. But this is what makes the tax collector such an interesting figure in Jesus' ministry -- they aren't "the little guy." Not only are they materially comfortable, but they also work hand-in-hand with the Roman occupation.
Nobody likes the IRS, especially when taxes are taking food off your table. But in the first century Judea, the disdain for tax collectors went far beyond economics. Tax collectors were traitors, Jews who not only accepted Roman occupation but enabled and supported it. Furthermore, the way tax collectors made money was by collecting additional money than what was required. This was not necessarily corruption -- Rome expected this from its collectors. So when John the Baptist instructs tax collectors to "collect no more than you are required to" (Lk. 3.13) he is asking them to essentially work without wages. To most Jews living under Roman rule, tax collectors were traitors and extortionists, one of the worst kinds of people.
Jesus reaches out to the tax collectors precisely because they are ostracized by their communities, especially by the religious order that saw close cooperation with Gentiles as straying from their religious identities. They are unique from lepers, prostitutes, the disabled, and other marginalized groups Jesus ministers to because tax collectors occupy a certain level of privilege and have power that these other groups do not. However, as a disciple Jesus expects Matthew to open his homes to all kinds of "sinners" and to sacrifice what privilege he has for the sake of others.
There are lots of people in the modern world who occupy comfortable positions of privilege and are active and willing participants in a system that oppresses and hurts others. The tax man serves as an archetype for the middle class who "sell out" to this system and cooperate with imperialism. It's comforting to know that there is a special place in Jesus' teachings and ministry that serve people like the tax collectors: people struggling with their conscience and own identity, and that Jesus even invites them into his closest circle.
