The parallel passage in Luke 6:12ff emphasizes the special nature of this choice even more formally and powerfully:
In those days
(Jesus) departed to the mountain to pray,
and he spent the night in prayer to God.
When day came,
he called his disciples to himself,
and from them he chose Twelve,
whom he also named apostles....
Although the passage from Matthew comes in the course of the normal rotation of Gospel readings in Ordinary Time, its timing today has special resonance, on account of the document issued yesterday by the Congregation for the Doctrine of the Faith in which the concept of Apostolic Succession figures prominently: particularly in distinguishing Catholic and Orthodox Churches from other ecclesial communities.
Very simply put, Apostolic Succession means that the Catholic and Orthodox Churches are ecclesial communities that have real, historical continuity with those twelve men chosen so specially by Christ.
The historical origins of other ecclesial communities are quite different: almost exclusively beginning with a dynamic individual or group of like-minded people who lived more than a millennium and a half after the death of the last Apostle and who decided to start their own church. Of course, that is not to disparage the faith of the individual believers in those communities or to say that the grace of the Lord is not at work in their midst. Indeed, many in the Catholic and Orthodox Churches sometimes can learn much from the faith and example of many Christians who are called Protestant.
However, real historic continuity is more than just trivia for a Christian community, for Christianity consists of more than just a book or immaterial promptings or good ideas.
As the Body of Christ, the Church is a continuation of the incarnational action of God and that gives special meaning and power to the real, historic continuity enjoyed by the Catholic and Orthodox Churches. The Catholic and Orthodox Churches are ecclesial communities over which the Successors of the Apostles have presided since the Apostles themselves passed on to them the responsibility that they in turn had received from the hand and mouth of Christ.
What we believe, what we celebrate, and what we do as Christians is more than just what comes out of our head or out of a book or out of the sky: it comes from Christ, who walked on this earth in a particular place and time and who in that place and time sent forth twelve particular men, beginning an unbroken chain of “being sent” to which we are blessed to belong.
Credo in... unam, sanctam, catholicam et apostolicam ecclesiam.