Before Jesus ascended into heaven, He gave some final instructions to His apostles - and by extension, to all disciples. These instructions defined the work He gave us to do while we live in this world. Hear His words: "All authority has been given to Me in heaven and on earth. Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age" (Matthew 28:18-20, NASU).
We carry out that God-given mission by sowing the seed of the Word of God in our world (Mark 4:14; Luke 8:11), both individually and collectively. As we do that, we trust in God's promise that, "...it will not return to Me empty, without accomplishing what I desire, and without this succeeding in the matter for which I sent it" (Isaiah 55:11, NASU). We accomplish this mission by publicly and privately teaching and preaching God's Word, living His Word in our individual lives, and supporting (with prayers, money and encouragement) the spreading of the gospel to the world.