Observations from Acts on Ministry Leadership

"News of this reached the church in Jerusalem, and they sent Barnabas to Antioch. When he arrived and saw what the grace of God had done, he was glad and encouraged them all to remain true to the Lord with all their hearts. He was a good man, full of the Holy Spirit and faith, and a great number of people were brought to the Lord.Then Barnabas went to Tarsus to look for Saul,  and when he found him, he brought him to Antioch. So for a whole year Barnabas and Saul met with the church and taught great numbers of people." (Acts 11:22-26)

Barnabas was an effective teacher and leader, but still recruited Saul/Paul to come to Antioch.   It's clear that they both taught and led at Antioch.  And God (who does not make mistakes) sent both men to the Gentile world (Acts 13:1-3). 

Paul and Barnabas go through many struggles and joys together, co-ministering, both operating (boldly!) as teachers and preachers.   This is plainly seen in these verses:
Acts 13:5, 7 42-43, 46, 51
Acts 14:3, 21, 27
Acts 15:2, 35

Then their disagreement comes (Acts 15:36-41), and they separate.  Barnabas takes John and goes back to his home in Cyprus.  Paul takes Silas and continues on in Asia Minor. 

All through the remainder of Acts, chapters 16-28, Paul is clearly the preacher, teacher, and leader.  He's the public face of the ministry team.  (Paul has many different helpers in these years.)   Never again is there an indication of co-leadership with another, the way he and Barnabas had operated.

Three thoughts for your consideration:
1. Ministry is a team effort.  God intentionally brings people together for His work, using our complementary strengths.  Paul could not have accomplished all that he did without help from others and their support. 
2. Perhaps the separation event in chapter 15, difficult as it was, was a transition between different phases of ministry, with different leadership needs.
3. Even if I'm correct about different phases of ministry, let us be clear that God is sovereign over all, and works through imperfect leaders.  There was effective ministry when Barnabas and Paul co-led, and effective ministry after they separated.