The Church Built and Blessed
Acts 9:31 (ESV) … “So the church throughout all Judea and Galilee and Samaria had peace and was being built up. And walking in the fear of the Lord and in the comfort of the Holy Spirit, it multiplied.”
The most feared persecutor became the most famed promoter of the gospel. Immediately after entering the city, Saul applied his years of rabbinical training in the Scriptures to proclaim Jesus in the synagogues. Saul was unashamed of the gospel and proved that Jesus is the Son of God and the Saviour. He confounded the Jews by actively debating and articulating the truth. After preaching in Damascus, Saul left for the region of Arabia. He then returned to Damascus over a period of three years (see Gal. 1:17). After these ‘many days had elapsed’ (Acts 9:23), Saul returned to Damascus with more force than ever, and the Jews hated him all the more for it, plotting to murder him. The Jews were ‘watching the gates day and night’ (v. 23), as these were the only normal ways in and out of the city. So the disciples created an escape plan, letting Saul out in a basket through an opening in the city wall (v. 25).
Saul then journeyed back to Jerusalem (v. 26). He had countless friends in Jerusalem, but now that he was a Christian there was no going back to them. He was starving for fellowship and tried to ‘associate with the disciples’ (v. 26). But, with the echoes of his former life still in the air, they were afraid of him, and Saul remained rejected and alone. But Barnabas ‘took hold of him’ and vouched for the authenticity of Saul’s conversion (v. 27). This began a friendship that would take them on a missionary journey together in Acts 13.
Saul found himself in Stephen’s position, arguing with the people and speaking out boldly in the name of Jesus. Stephen’s last prayer for God to forgive and save the people who had assented to his death (7:60) had been answered in a most profound manner. Saul was persecuted by the Hellenistic Jews and was sent away to the port town of Caesarea, from where he travelled back to his home-town of Tarsus (9:30). The church kept on growing and being built up, focusing on the fear of the Lord and being comforted by the Holy Spirit (v. 31). 
It is not only the blood of the martyrs that is the seed of the church. God can use times of rest and tranquility as well as times of rage and tribulation. He brings His people into green pastures and beside the still waters from time to time. He makes even our enemies to be at peace with us.
A truce now seems to have been accepted in Palestine. Jews and Christians decided to leave each other alone. Judaism set its sails towards the sunset in its stubborn refusal to acknowledge Jesus as Messiah. The church dropped anchor for the time being before spreading its sails again in search of new worlds to win for Christ.
In this lull the believers grew in grace and increased in the knowledge of God. The Holy Spirit was evident in their gatherings everywhere throughout the Holy Land. Numbers continued to be saved. It was a welcome respite. 
Wong, J.-M. (2010). Opening up Acts(pp. 75–76). Leominster: Day One Publications. Phillips, J. (2009). Exploring Acts: An Expository Commentary (Ac 9:31). Kregel Publications; WORDsearch Corp.