Jesus Christ, after His death, burial, and resurrection commanded His followers to "Go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you."
We see two important messages in this: 1) we need to live according to Jesus' words, and 2) we need to present the message to others so that they have the same opportunity to learn from Him and be saved from their sins.
A disciple is a follower, student, or apprentice, of our master Jesus Christ having the goal of becoming like the master.