Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed them. And when they saw him they worshiped him; but some doubted. And Jesus came and said to them, “All authority in Heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you; and lo, I am with you always, to the close of the age.” (Matthew 28:16-20)
The expression “The Great Commission” is commonly found in Reformation theologies to refer to this command of Christ to the disciples to preach the Gospel to the world. While the expression is not unknown in Catholic usage, it is not commonly used, and typically acquires a different meaning. For non-Catholics it represents a general command to all believers; whereas, for Catholics it constitutes primarily a command to those whom Christ appointed to carrying out His ministry, that is the Apostles, and the successors to their ministry, the bishops.
The Catholic understanding follows from the fact that Matthew records the Apostles as the bearers of the obligations and the authority Christ committed to the Church. The text mentions only “the eleven,” that is, the Apostles minus Judas Iscariot. These are those whom Christ chose to take His place as pastors of His flock. This is the context of the command given to them to make disciples and to baptize, and of His promise to remain with them “to the end of the age.”
This also corresponds to Christ’s other commitments of authority and responsibility to the Apostles, such as the power of the keys (Mt. 16:13-18 and Mt. 18:8), and the forgiveness of sin (John 20:19-23). Since the Apostles all died, it also presumes that “to the end of the age” others will take their offices after them, as Matthias took that of Judas (Acts 1:15-26). Indeed, everywhere the Apostles went they appointed successors, as Paul appointed Timothy and Titus. In the 2nd century St. Irenaeus of Lyon will list the successors of Peter in the Roman See, in contradistinction to the heretics of his day who can claim no such authority.
Christ is also with the Church “to the end of the age” in other ways, as well. However, He is uniquely and most importantly Present in the Holy Eucharist, by means of which His Holy Sacrifice is remembered and made Present, in the gift of Himself in Holy Communion, and by remaining with us in our tabernacles. In all these ways the continuity and unity of Christ’s redemptive ministry is guaranteed until He comes again (cf. John 16:13-15, 17:2-21).