Near the heart of understanding why the poor are blessed by the gospel is the simple fact that for the church, the poor are sacramental subjects.
What does that mean?
In a very simplified sense, sacrament is the stuff of life through which God meets us. Christianity is not some simple intellectual ascent to spiritual ideas nor the rejection of the physical world as unimportant. God, in Christ, by the incarnation, embraces material existence and brings it into Himself. So stuff like water, bread, wine, oil become means of communicating the love of God to us.
Yet Jesus says of the poor that what we do for them we do for him. In the body of the poor we meet our Lord as sacramental “subject” because they are not mere “objects.” Capitalist and Socialist systems objectify the poor. They become (in both cases) objects of pity and oppression.
But as Christians we meet in the life of a poor man a person that must be treated with dignity and love–not as a mere object of our pity. We must understand the homeless woman who has been abused and suffered multiple rapes–that one we find ugly and offensive–is the embodiment of our Lord to be approached with awe. Those whose poverty is less visible like the stranger from another land, be they immigrant or international student, is the bodily expression of our Lord’s loneliness, not just a political problem or potential proselyte.
As the church we must understand this because in the other sacraments God gives to us himself. In the poor person–the subject–we have the chance to give ourselves to God.