Jesus Christ called people to take up their cross and follow Him. He called them to be "disciples"... learners at the feet of Jesus. Then He did something truly mind-boggling and humbling for His followers. He gave them the responsibility to make more followers. Shortly afterwards, He went back to Heaven and sent His Spirit to empower for that task.
When the promised Holy Spirit came, the world was lit on fire (almost literally--see Acts 2:3). Almost immediately, His people, the Church, "devoted themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer" (Acts 2:42). That was the recipe for mature Christians back then and it's still ours today.
Not only did Jesus call his followers to make more followers and mature in their relationship with Him, but He gives each unique gifts and abilities to keep lighting the world on fire, showing that Jesus has an answer for all the heartbreak and ugliness in our world and so we pray that His kingdom come, His will be done, on earth as it is in Heaven.