When the Lord Jesus commissioned His followers to make disciples of all nations, they were to be His witnesses in Jerusalem, in all Judea and Samaria, and to the ends of the earth. During His time with His disciples, Jesus revealed Himself as the Son of God and trained them for the task ahead.
“Peace be with you. As the Father has sent me, so I am sending you.” – John 20:21
And He promised the Holy Spirit to empower and to guide them. There as a spectacular beginning to the work of missions on the day of Pentecost. The Holy Spirit came as promised and the gospel preached to an audience —
At that time there were devout Jews from every nation living in Jerusalem. – Acts 2:5
A tremendous response followed and thousands believed.