The mystery of the poor is prior to the ecclesial mission, and that mission is logically prior to the established church. What Jürgen Moltmann wrote many years ago is still true: “It is not that the Church ‘has’ a mission, but the reverse; Christ’s mission creates itself a Church. The mission should not be understood from the perspective of the Church, but the other way round.” It is not that the Church already existed, and later asked what to do for and with the poor, as if the Church were formally established prior to its relationship with them, or as if its way of carrying out that option were unrelated to the essence of the Church, which remains unchangeable throughout history.
Jon Sobrino, No Salvation Outside the Poor, 21).
The greatest structural temptation for the Church arises out of its relational character. On the one hand, the Church is entrusted with the tradition of the kingdom and the requirement to make the kingdom a reality; on the other hand it is not itself the kingdom. This combination of factors puts the Church in a situation of “concupiscence,” that is, of wanting to be, by identity, that which in fact it can only point to and serve, namely, the kingdom of God. In consequence, the possibility of conflict is always present; and when a particular situation clearly shows the difference and distance between Church and kingdom, the conflict breaks out—and cannot but break out—spontaneously. The discovery that the kingdom of God is the ultimate reality has brought an elemental truth to light: the Church, even in its entirety, is not absolute and therefore its structure is open to criticism.
~ Jon Sobrino, The True Church of the Poor, 202.