As I was reading your question a prime example of a “strong bond eventually weakening between two people” came to mind. So I will give that example and then seek to answer your good question. In Acts chapter 9 we have the account of the conversion of Saul of Tarsus, a true miracle of grace since Saul had been the greatest persecutor of the church as we see in Acts 8:1 & 3, “Now Saul was consenting to his (Stephen’s) death. At that time a great persecution arose against the church which was at Jerusalem…As for Saul, he MADE HAVOC OF THE CHURCH, entering every house, and dragging off men and women, committing them to prison.” After Saul’s conversion (recorded in Acts 9:1-18) we see that he “preached the Christ in the synagogues, that He is the Son of God” (verse 20). How did people react to Saul’s “dramatic change?” In verse 21 we read that “all who heard him were AMAZED.” Later, when Saul came to Jerusalem to join fellow-believers, we read that “they were all AFRAID of him, and did not believe that he was a disciple” (verse 26). Yet in the very next verse we read of one who stood by Saul and defended him, “But Barnabas took him and brought him to the apostles. And he declared to them 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.” When ALL were against Saul, BARNABAS befriended him and at that moment a very “strong connection” was formed between these two. The next time we read of Saul and Barnabas is in Acts 11:22-26 where “Barnabas departed for Tarsus to seek Saul… and he brought him to Antioch” (verses 25-26) where new believers in Christ needed to be established in the faith. The next verse informs us that “for a whole year they assembled with the church and taught a great many people.” Surely their labors together over such a long period of time only served to “strengthen the bond between them.” In Acts 13 we find them together again in Antioch where they were seeking the Lord’s Mind with others and in verse 2 we read, “As they ministered to the Lord and fasted, the Holy Spirit said, ‘Now separate to Me Barnabas and Saul for the work to which I have called them.” This was the beginning of “the first Missionary journey” where they labored together and were privileged to win many souls to Christ for a period of nearly 2 years before returning to Antioch. Again, their labors together, along with the persecutions they suffered, resulted in a deepening of the bond between them.

I truly wish we could read on and see a “lifetime bond” forged between these two faithful servants of Christ, but such was not the case. We will now read of the “weakening of this bond” in Acts 15:36-40, “Then after some days Paul (Saul’s new name) said to Barnabas, ‘Let us now go back and visit our brethren in every city where we have preached the word of the Lord, and see how they are doing.’ Now Barnabas WAS DETERMINED TO TAKE WITH THEM JOHN CALLED MARK. BUT PAUL INSISTED THEY SHOULD NOT TAKE WITH THEM THE ONE WHO HAD DEPARTED FROM THEM IN PAMPHYLIA…THEN THE CONTENTION BECAME SO SHARP THAT THEY PARTED FROM ONE ANOTHER. And so Barnabas took Mark and sailed to Cyprus; but Paul chose Silas and departed, being commended by the brethren to the grace of God.” How sad! These two men who had been the closest of friends and labored together for many years, now “parted from one another.” And we never read of them being together again after this.

Now we must tackle your main question. Why did the Lord bring these two men together in the strongest of bonds knowing that their bond would be weakened? We saw that the Lord definitely used Barnabas to defend Saul and to commend him to the saints in Jerusalem. We also saw that the Lord used these two mightily to establish the young saints at Antioch and then to canvass the cities of Asia Minor with the gospel. This means “the Lord had a PURPOSE in bringing them together.” Then we saw these two disagree on a very important matter and part company. Was this the Lord’s purpose? No, for the Lord desires to see unity and harmony between His people as we see in Philippians 2:1-3, “Therefore if there is any consolation in Christ, if any comfort of love, if any fellowship of the Spirit, if any affections and mercy, fulfill my joy by being like-minded, having the SAME LOVE, being of ONE ACCORD, of ONE MIND. Let nothing be done through selfish ambition or conceit, but in LOWLINESS OF MIND let each esteem others better than himself.” It was the Apostle Paul who was inspired to write these words yet as we saw Paul failed (as did Barnabas) to put them into practice. Instead of “working out their differences” their “contention became so sharp that they parted from one another.” Now we could try to figure out if one was more to blame than the other, but the lesson here is THEY BOTH FAILED. The Lord DID NOT FAIL! The Lord brought them together to form a bond of friendship and to labor together and His will was for this bond to continue throughout their lives. Yet the Lord faithfully tells us of the “weakening of their bond” that led to their separation to show us how even the “best of friends” can disagree and if they don’t put verses like Philippians 2:1-3 into practice THEY WILL FAIL. Believers still have the “flesh” (the “sinful nature” that is still in us…see Romans 7:16-18) and if we don’t “reckon ourselves to be dead to sin” (see Romans 6:6-11) and allow the Holy Spirit to control us (see Galatians 6:16-23), we too will find ourselves failing in relationships (with our fellow –believers, our children, our spouse, our siblings, etc.) which are meant to be life-long bonds.  (443.1)  (DO)