Taught and preached the word of the Lord

Acts 15:22-41
Then the apostles and elders, with the whole church, decided to choose some of their own men and send them to Antioch with Paul and Barnabas. They chose Judas and Silas, two men who were leaders among the brother. With them they sent the letter.
The men were sent off and went down to Antioch, where they gathered the church together and delivered the letter. The people read it and were glad for its encouraging message. After spending some time there, they were sent off by the brothers with the blessing of peace to return to those who had sent them. But Paul and Barnabas remained in Antioch, where they and many others taught and preached the word of the Lord.
Barnabas took Mark and sailed for Cyprus, but Paul chose Silas and left, commended by the brothers to the grace of the Lord. He went through Syria and Cilicia, strengthening the churches.
This chapter is a turning-point in Acts. The center now shifts away from Jerusalem and the apostles, with the emphasis on the mission to the Gentiles and the new churches.
A 'sharp argument' about John Mark results in two missionary campaigns instead of one. Barnabas, the 'encourager', no doubt helped his young nephew to make the grade and eventually win Paul's approval.
Barnabas and Mark return to Cyprus. Paul takes Silas and revisits the mainland cities of the first campaign.
Why?
When the meeting made decision so they wrote letter and sent Paul, Barnabas and two brothers with blessing of God from apostles to church of Gentiles.
Barnabas is a encourager, to helped his young nephew Mark to make the grade and eventually win Paul's approval. So encourage the weaker is our love and mission to every Christian.
The letter from Jerusalem encouraged church in Antioch and other places.
Taught and preached the word of the Lord is the job to every Christian either like Paul and Barnabas.
How?
Love others and encourage frustrated weaker, help them to stand up through word of God.