Each follower of Jesus is related to every other believer as a spiritual brother or sister. There is a wonderful equality in His family. However, He has appointed leaders who should be respected (Hebrews 13:17). They are not leaders in a military or business sense, but God has given them authority to lead His people into His truth and to follow His ways. Paul says in Ephesians 4:11-13 that they had apostolic, evangelistic, prophetic, and teaching functions - to model those ministries and equip other believers to serve the Lord according to their gifts. They were coordinated by elders whose purpose was to enable the church to grow as a united family, working together for the Lord (Titus 1:6-9).
 
But some, perhaps proud or hot-headed people, thought that the equality in God's family gave them a right to be independent of their leaders. They did not respect the Elders who God had placed over them. They did not honour the self-sacrificial loving care that they demonstrated, nor did they value being taught or rebuked (Titus 1:10-13). In short, they did not love their leaders, and therefore created disunity in the fellowship.
 
Of course, there were some leaders who did not demonstrate those characteristics, who flaunted their loveless authority and failed to set the church on a gospel course (2 Peter 2:1-3). But Paul was not talking about them. He wanted the church in Thessalonica to support their hard-working leaders who were full of gospel-courage (many of whom suffered persecution). Those people were God's appointees; their passion for Jesus in the face of many challenges and persecution was to be be honoured. It was God's plan that they should be loved by those they served, and that love should be the governing characteristic of the fellowship – encouraging growth in maturity and attracting unbelievers to Jesus.
 
Despite the example of some who exploit their position for their own purposes, or who have substituted human agendas for gospel-priorities (2 Timothy 4:3-4), the principle remains that spiritual leaders are responsible for the people they serve (Acts 20:28). Their service is never fully rewarded in this life, their hard work is mostly unseen, and their love suffers many rejections. They do not serve the gospel because of what they get out of it, but because they know the Lord has called them, and they are glad to be obedient. Support them, pray for them, obey them, serve gladly under them and love them sincerely. That is the way that the Body of Christ is built in unity for His glory.