After the gospel triumphs of the previous chapters, Luke's blunt honesty about the fall out between Barnabas and Paul makes for distressing reading:
There arose a sharp disagreement, so that they separated from each other.
Ouch. This was incredibly sad. We shouldn't read this without weeping.
Thankfully it wasn't the end of the story. There was reconcilliation eventually. And God providentially used it to create two missions teams instead of one. But we shouldn't think about it positively for that reason. Luke is telling us about an unpleasant and damaging reality, and his account is all the more persuasive to Theophilus and us for not massaging out the difficult bits.
I think its interesting that they fell out over John Mark. Over a matter of personnel not of principle or doctrine. I have seen sharp disagreements that started as matters of personnel or personality clash that, in subsequent years, hardened around doctrinal themes. But weren't that originally. When we see major disagreements between believers in our generation over apparently doctrinal themes it is always worth a quick check back to see how and where they emerged, and whether it was always doctrinal. Trying to figure out how to put the wheels back on the wagon may be easier if we figure out why they fell off in the first place.
However, by God's grace it isn't the end. In fact we read something rather remarkable in 16:1: there was a disciple called Timothy, in Lystra. Remember Lystra, the place where everything seemed to go wrong with superstitious pagans sacrificing to the apostles and jealous mobs stoning them nearly to death? The place where it seemed there was so little fruit. God loves Lystra! He has disciples in unlikely places.
Paul takes Timothy with him. This new mission team is now recruiting. It seems to have happened much like it happened to Paul and Barnabas in Antioch, with the Holy Spirit working and the laying on of hands in commissioning (see 2 Tim 1:6-7). Apparently the commissioning of Paul and Barnabas by the Spirit in Acts 13 wasn't a one off. It was the beginning, but now others are being added.
I love the fact that so quickly after the council in Acts 15 establishes that circumcision is not necessary for salvation and that Gentile believers don't need to be under the Law, that Paul circumcises Timothy. It has led some to accuse him of rank hypocrisy. I don't think its anything of the sort. Having established that it is not a salvation issue Timothy is free to not be circumcised. But they do it because there are Jews in the places they want to evangelise who know his father is a Greek. In other words Timothy makes the sacrifice (and what a sacrifice!) for the sake of culturally relevant evangelism. And Paul is prepared to flex his approach to such a degree that he takes part in a rite he knows is wholly unnecessary and redundant for the sake of culturally relevant evangelism.
So they travel, delivering the Jersualem verdict: Gentiles are not under the Law for justification. And the result: the churches were strengthened in the faith and numbers grew daily (16:5). Praise God. Let's pray for the same.