Mark 16:15, And He said to them, “Go into all the world and proclaim the gospel to the whole creation.”
The whole creation! This is quite the weighty task for 11 disciples (later to be 12 when they bring on Matthias). Not only was this a weighty task, but it was also impossible for these 11 men. They began in Jerusalem and went as far as modern-day Italy. In their lifetime, they could not reach Russia, all of Europe, east Asia, Africa, North and South America, Latin America, and so on. They knew this. Thus, they passed their work down to the Church.
This is why we have tradition, or παράδοσις (paradosis)—things passed down to the Church. These include the proclamation of the Gospel and the means of grace (Word and Sacrament). What the Holy Spirit began in the apostles, He continues in the Church. Thus, the mission of the apostles has not ended. The Church continues their work—rather, the work of Christ through the Holy Spirit. This mission includes every single Christian, not merely the Pastor and his chosen Christian educators. Every single Christian is responsible for the mission of the Holy Spirit to proclaim the Gospel to the whole creation.
This is why Luther emphasised vocations. Every Christian has been given multiple vocations. For example, I carry the vocations of son, brother, fiancé, student, gamer, poet, photographer, musician, employee, and soon to be vicar. How can I preach Christ in these vocations? That is for me to discover as the Holy Spirit leads my participation in the Church. Thus, consider your own vocations. As you participate in the Church, how might the Holy Spirit be leading you to proclaim Christ to all of creation?
The Lutheran Column 