In his pioneering work “The Ten Commandments and The Beatitudes: Biblical Studies and Ethics for Real Life,” theologian Lúcás Chan argues that the Commandments and the Beatitudes are the twin moral pillars of the Bible. He also makes the case that we need to attend to the Beatitudes because these are the steps we must learn if we want to follow Christ. Chan explains that the Gospel of Matthew’s Beatitudes are a ladder of ascent. We start with the first, and from there step up to the next. This is a lesson plan for following in the (ascending) footsteps of Christ. Chan illustrates this by commenting on the first two Beatitudes. The “poor in spirit” in the first Beatitude (“Blessed are the poor in spirit, for theirs is the kingdom of God”) are not simply people who are sad. Unfortunately, some preachers, not knowing what “poor in spirit” meant, took it to be a softening Luke’s more stark “Blessed are the poor.” In fact, it’s the contrary. Matthew’s “poor in spirit” correlates with the word “beggar.” It is the poverty of someone who has no advocate at all, but God. Their poverty is the most absolute: they have no support and no dependency and so even their spirit is poor. It is important for us to realize that this is the point of departure for Christian discipleship: to witness and respond to the poor in spirit. All other Beatitudes are formative stances that allow us to respond to the poor in spirit. Chan explains that when we turn to the second Beatitude, “Blessed are those who mourn, for they will be comforted,” we must not take our eyes off the poor in spirit. Again, unfortunately, too many of us have heard sermons that suggest that this means if you have suffered a loss, you must mourn. Unresolved grief festers, preachers add. While that is perfectly good advice about grief, it completely misses Jesus’ sermon. Those who will be comforted are those who are mourning the condition of the poor in spirit. Mourning or empathy is effectively the wake-up call of discipleship. Discipleship means being able to recognize and feel for the condition of the poor in spirit. The other Beatitudes follow as instructions from Jesus about how to grow in care for the poor in spirit. It is effectively a seven-step program that starts with empathy and moves to meekness, that is, to becoming teachable. Then it moves to the ascetical practices of hungering and thirst, allowing us to enter into solidarity with the poor, developing practices of mercy, purifying oneself, working for peace, risking persecution, risking insult and finally risking all forms of injustice. Chan’s remarkable read of the Beatitudes equips us well to respond to Pope Francis’ call to welcome the immigrants and refugees whose plight we dare not ignore, whose conditions we must mourn, and whose own cries echo those of others long ago ignored. This summons is urgent and above all Christian. Chan reminds us that the early Christians responded to the Sermon on the Mount. They put on Christ by putting on the Beatitudes precisely by welcoming the poor in spirit who were in their midst. In his book “The Rise of Christianity,” Rodney Stark confirms this. Christianity grew in urban areas that in the first century were marked by “social chaos and chronic urban misery.” The population density was extraordinarily high, unlike anything today. At the end of the first century, Antioch’s population was 150,000 within the city walls — 117 people per acre. Rome, with a population of 600,000, was much worse. Moreover, with high infant mortality and short life expectancy, these cities required “a constant and substantial stream of newcomers” in order to maintain their population levels. The overpopulated cities were made up of strangers. These strangers were treated well by Christians. All kinds of financially secure Christians welcomed the newly arrived immigrants. This welcoming was a new form of incorporation. “To cities filled with newcomers and strangers, Christianity offered an immediate basis for attachments,” Stark writes. “To cities filled with orphans and widows, Christianity provided a new and expanded sense of family.” Stark’s compelling argument is simply that in a merciless empire, Christianity grew when Christians took charge. They did this by welcoming not only family and tribe. More important, they welcomed the poor in spirit. Keenan is the Canisius Professor of Theology at Boston College.