MATURE FULLNESS OF CHRIST
In Ad gentes, no. 9, the II Vatican Council Fathers tell us how the Church regards her own mission to preach the Gospel to all nations. The command given to her by Jesus (Mk. 16:14) is not something that she has to plan and work out totally on her own. The Lord is with her (cf. Mk. 16:20). She must follow His lead. He is preparing the world for His final coming. The Church’s missionary activity is simply the gradual manifestation of God’s plan for humanity: “The period, therefore, between the first and second coming of the Lord is the time of missionary activity when, like the harvest, the Church will be gathered from the four winds into the kingdom of God. For the Gospel must be preached to all peoples before the Lord comes (cf. Mk. 13:10).”
The many great works inspired and carried out by her saints and great men and women are not the result of the Church’s planning. They are works of the Holy Spirit preparing the world for Jesus’ final coming and a manifestation of that planning of the Holy Spirit: “Missionary activity is nothing else, and nothing less, than the manifestation of God’s plan, its epiphany and realization in the world and in history; that by which God, through mission, clearly brings to its conclusion the history of salvation.”
The Church’s first duty then, even before trying to the read the signs of the times, is to listen to what the Lord has to say to her (cf. Rev. 2:7; 2:11; 2:17; etc.). Then she will be ready to judge things as her Master does and will choose to do those things that truly prepare for His final coming. One of the things she will always choose to do is missionary activity ad gentes [to the nations].
The benefits of this kind of missionary activity are enumerated by the Council Fathers: “Through preaching and the celebration of the sacraments, of which the Holy Eucharist is the center and summit, missionary activity makes Christ present. It purges of evil associations those elements of the truth and grace which are found among peoples, and restores them to Christ their source who overthrows the rule of the devil and limits the manifold malice of evil.”
Missionary activity prepares the Church and the world for the return of Christ: “Missionary activity tends towards eschatological fullness; by it the people of God is expanded to the degree and until the time that the Father has fixed by his own authority.” The expansion of the people of God that is mentioned in the document is not only a physical growth in size. It is a maturation process. The Church is thereby growing to the full maturity of Christ, whose mystical Body she is: “By missionary activity the mystical Body is enlarged until it reaches the mature fullness of Christ (cf. Eph. 4:13). The spiritual temple where God is adored grows and is built up on the foundation of the apostles and prophets (Eph. 2:20).”