Saul of Tarsus

Where is "Tarsus" (Acts 11:25)?
Tarsus was a major port city and the capital of the Roman province of Cilicia, which was located in the southern Mediterranean coast of what is Turkey today. Tarsus was about 80 miles (130 kilometers) northwest of Antioch.

Why did Barnabas think that Saul would be in Tarsus?
Saul/Paul was "born in Tarsus" (Acts 22:3) and had been sent "out to Tarsus" (Acts 9:30) by the church in Jerusalem after "Barnabas took him and brought him to the apostles" (Acts 9:27) and they "found out" (Acts 9:30) about a plot to kill him (see Saul Escapes in a Basket).

What was Saul like when he first left Tarsus?
A promising student who was chosen to study in Jerusalem under "Gamaliel" (Acts 22:3), the most prestigious teacher of Judaism at the time, Saul was a model Jew: "... If anyone else thinks he may have confidence in the flesh, I more so: circumcised the eighth day, of the stock of Israel, of the tribe of Benjamin, a Hebrew of the Hebrews; concerning the law, a Pharisee; concerning zeal, persecuting the church; concerning the righteousness which is in the law, blameless" (Philippians 3:4-6).

How might Saul's family and friends in Tarsus have felt about him when he persecuted the church?
They most likely took great pride in him. After all, Saul became someone for whom the high priest wrote "letters" (Acts 9:2) of introduction.

As what did Saul return to Tarsus, and how did his family and friends receive him?
Saul returned to Tarsus as a hunted man and an enemy of Judaism. While he never talks directly about his family's reception, if "all things" in this quote include his family and friends, they most likely disowned him: "Yet indeed I also count all things loss for the excellence of the knowledge of Christ Jesus my Lord, for whom I have suffered the loss of all things, and count them as rubbish, that I may gain Christ" (Philippians 3:8). Note that he calls "all things" "rubbish" not in the absolute sense but relative to "the excellence of the knowledge of Christ Jesus."

Is such a reception the exception or the norm?
When a member of a non-Christian family or group of friends turns to Christ, rejection and even persecution by the family and friends often follow. Even Jesus Himself was rejected by His earthly family during his earthly ministry and declared, "A prophet is not without honor except in his own country, among his own relatives, and in his own house" (Mark 6:4). And non-Christian friends of a new Christian almost always drift off. The only way to keep them is to tell them about Jesus so that they become siblings in Christ.

What had Saul been doing in Tarsus since his return?
While he doesn't state it, given the fact that he risked his life to "boldly" (see Acts 9:24 below) preach the Gospel in both Damascus and Jerusalem, it is hard to imagine Saul not dedicating at least part and probably a significant amount of his time in Tarsus to evangelism.

Why did "Barnabas depart for Tarsus to seek Saul" (Acts 11:25)?
When Saul told the apostles and Barnabas in Jerusalem "how he had seen the Lord on the road, and that He had spoken to him, and how he had preached boldly at Damascus in the name of Jesus" (Acts 9:27), he most likely included the Lord's declaration to Ananias that he (Saul) was "a chosen vessel of Mine to bear My name before gentiles" (Acts 9:15). It was time for the chosen vessel of the Lord to be put to full use, starting with a "whole year" (Acts 11:26) of teaching "a great many" (Acts 11:26) new gentile believers in Antioch.