“And some days after Paul said unto Barnabas, Let us go again and visit our brethren in every city where we have preached the word of the Lord, and see how they do.” (Acts 15:36 KJV)
Follow up. One of the most important aspects of good customer service. It keeps good relationships good. It makes bad ones better. It prevents minor mistakes from becoming major. It keeps major mistakes from becoming unsalvageable. Who plants a seed and then does not water it? The decision to follow up is a management decision. This provides God two opportunities. One, an opportunity to increase the work force. Two, an opportunity to test your resolve and your faith.
It always seems that just when you have resolved to do something, a kink is found. Few disagree with what needs to happen, but someone has issue with how it ought to happen. In this case, an unresolved issue of trust and longevity resurfaces. Before we can check on others, the Lord has a way of giving us an opportunity to check on ourselves. A general reminder that it is in our weakness and in our trust of His strength that we are strong. Instead of three potential workers, a fourth (Silas) now finds an open position. God works in ways that we do not always understand up front. A few that we do not understand in reflection either. Yet, He always finds a way to add workers, keep the work going, and survive even the sharpest of disputes among those who understand the maker of peace the best. He gives us material even though it is the material for discussion that we would like the least.
Is it wrong to question such in-fighting at all? That may be more than I can answer except to say that it is not tight discipline that is the trademark of a Christian; that trademark is love (see John 13:35). Then again, that may not help much either. Love is not always seen by the absence of disagreements, but in the patience and the will that it takes to resolve them. The bits and pieces that we get of real love this side of Heaven are still wrestled out and only understood better as we step further into Jesus. Notice that in verse forty when they depart, they depart with the full recommendation of the brethren. They depart unto the grace of God.
“And the contention was so sharp between them, that they departed asunder one from the other: and so Barnabas took Mark, and sailed unto Cyprus; And Paul chose Silas, and departed, being recommended by the brethren unto the grace of God.” (Acts 15:39-40 KJV)