To do what? Well, we can’t save anyone—that’s God’s work. As noted above in this verse, we are God’s handiwork, created in Christ to do good works prepared by him in advance before the foundation of the world. So, God does the saving with a purpose for us in mind.
But, honestly, what is it? Let’s let Jesus tell us clearly. Maybe borrow some of his words while here on earth. “But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth” (Acts 1.8b). Jesus’ witnesses! And we see in Matthew an even more clear role that we saved souls are to be about. “All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations” (vs. 28.18,19). Discipleship or disciple maker!
He explained all nations in Acts. First at home, then in regions around you, followed by cultures unlike you, and as far as you can go, making disciples of the gospel of Jesus Christ. God saves—we witness and disciple! And he has made two absolute promises for success. He is going to be with us in our process/work even to the end of this world, and he has sent the Holy Spirit to empower our efforts. That happened at your salvation! See, he wants to make sure your discipleship is effective.
But even more telling is the fact that he modeled ‘discipleship’ for us. He discipled twelve (including Paul), and the rest is history. So, since victory is assured, get in the game being his witnesses and disciple makers wherever he places you. Your joy will overflow.