Jesus called people to be disciples at the beginning of his public ministry. As he ascended to heaven at the end of his time on earth, he told them to "go and make disciples". Those in the early church are referred to as "disciples".
What is a "disciple"?
Merriam-Webster's Dictionary defines "disciple" this way:
1: one who accepts and assists in spreading the doctrines of another: such as
a. in Christianity one of the twelve in the inner circle of Christ's followers according to the Gospel accounts
b. a convinced adherent of a school or individual, such as a disciple of (Sigmund) Freud's theories of psychology
As we can see by what I have highlighted in bold, a disciple "accepts" and "assists in spreading"--doesn't just believe certain things, but practices those things. When Jesus started out, he gathered people whom he taught about how to live--loving God and loving neighbor the two greatest things. It wasn't just about agreeing with him that these are good ideas--it was about DOING them too. It's not just talking the talk, it's walking the walk.
And then at the end of his time on earth he told them to keep doing it in their own lives, and that doing it in their own lives meant teaching other people to do it in THEIR own lives. And it must have worked, because those who are part of churches are described as "disciples"--as the passage from Acts 14 indicates. So they, "accepted and assisted in spreading" the Good News of Jesus as savior--they believed it for themselves, and lived it out in spreading it to others.
And that is what the church should be today too--disciples of Jesus who accept and assist in spreading. And doing so as "convinced adherents"--again, talking the talk and walking the walk. Living in a different way, with different priorities, than it would seem the rest of the world lives and has.
Part of it is continuing to learn what that means as the world around us changes and adapts to new knowledge and more understanding of things. So we need to keep on growing in our own understanding--we can't assume that "I've got this" because we learned some basic things in third grade Sunday School.
And the other part of it is continuing to live that out in the constantly adaptive way that the constantly adapting world calls us to. Even in our own lifetimes, communications have changed. Our awareness of the rest of the world has increased. Medical science has made things possible that we could have never imagined not that many years ago. We have become increasingly diverse, and aware of many more subtle nuances about human life. Yes, being a disciple has the same foundations of loving God and loving neighbor. But what that looks like is very different from what it was.
So talking the talk and walking the walk needs our focused attention. And the world needs us to talk the talk and walk the walk, because not enough people feel loved by God and by neighbor. We are the ones called as disciples to live that out and let them know.
16 Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed them. 17 When they saw him, they worshipped him; but some doubted. 18 And Jesus came and said to them, ‘All authority in heaven and on earth has been given to me. 19 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, 20 and teaching them to obey everything that I have commanded you. And remember, I am with you always, to the end of the age.’
21 After they had proclaimed the good news to that city and had made many disciples, they returned to Lystra, then on to Iconium and Antioch. 22 There they strengthened the souls of the disciples and encouraged them to continue in the faith, saying, ‘It is through many persecutions that we must enter the kingdom of God.’ 23 And after they had appointed elders for them in each church, with prayer and fasting they entrusted them to the Lord in whom they had come to believe.
24 Then they passed through Pisidia and came to Pamphylia. 25 When they had spoken the word in Perga, they went down to Attalia. 26 From there they sailed back to Antioch, where they had been commended to the grace of God for the work that they had completed. 27 When they arrived, they called the church together and related all that God had done with them, and how he had opened a door of faith for the Gentiles. 28 And they stayed there with the disciples for some time.