"But we request of you, brethren, that you appreciate those who diligently labor among you, and have charge over you in the Lord and give you instruction, and that you esteem them very highly in love because of their work. Live in peace with one another." (1st Thessalonians 5:12-13)Darby gives a slightly different translation of this passage which I believe is more consistent with the literal Greek text. "But we beg you, brethren, to know those who labour among you, and take the lead among you in [the] Lord, and admonish you, and to regard them exceedingly in love on account of their work. Be in peace among yourselves." (1st Thessalonians 5:12-13 Darby)
What is interesting is that Paul writes directly to the church and not to these men. Paul did not recognize some hierarchical, top-down, control structure within the church. When Paul had something to say to the church he said it to the church. While leadership was present, they did not form a kind of filter between Paul and the church proper. They were there to serve the church, not to represent it or to lord themselves over it.
Jesus' teaching forever changed how we perceive (or should perceive) leadership. "The kings of the Gentiles lord it over them; and those who have authority over them are called 'Benefactors'. But it is not this way with you, but the one who is the greatest among you must become like the youngest, and the leader like the servant." (Luke 22:25-26) Jesus moved leadership from the top to the bottom, the head to the tail, and from the prince among men to the servant of all. Those who are called leaders are to be servants to the church; laboring for the church and admonishing, with gentleness rather than harshness, all to live a godly life. Leaders should see themselves as the servants of the church; sent to serve them, not to be served by them. For even Jesus "did not come to be served, but to serve." (Mark 10:45)
To the degree to which they serve, and serve well, we ought to esteem them and to love them well in return. Those who serve well are worthy to be loved, not just for who they are, but also for their work they do. Paul repeatedly calls their calling a labor and a work. "It is a trustworthy statement: if any man aspires to the office of overseer, it is a fine work he desires to do." (1 Timothy 3:1) Leadership, when done right, is a work and we ought not to forget the sacrifice and toil that our leaders expend for our sake. They labor out of love for us and we ought in return to love them for their work and sacrifice. They work for us that we might be free to experience the blessings and protections of christian fellowship as the church of Jesus Christ.
Finally, Paul exhorts us to live in unity and harmony with each other. The write of Hebrews describes the perils of strife and division, especially between the church and their leaders. "Obey your leaders and submit to them, for they keep watch over your souls as those who will give an account. Let them do this with joy and not with grief, for this would be unprofitable for you." (Hebrews 13:17) Sometimes we forget that God has assigned them a job within the body of Christ. We need to be as serving towards them in their role and function as they are towards us in our role and function. While we are needed in the Body of Christ, so are they. However, they are not another class of people, there should be no class warfare within the church, rather they are just like us and have been given a calling and a function within the church, just one that differs from ours. As we would like people to honor and respect who we are in Christ, so let us do also to them and let us learn to live together in unity and harmony to the glory of the Lord.