“Let all who are under a yoke as bondservants regard their own masters as worthy of all honor, so that the name of God and the teaching may not be reviled. Those who have believing masters must not be disrespectful on the ground that they are brothers; rather they must serve all the better since those who benefit by their good service are believers and beloved. Teach and urge these things.” (1 Timothy 6:1–2, ESV) 

Paul is not endorsing slavery in these verses. Instead, he is addressing a reality that existed during that time in history. Slavery was common in the Roman Empire, and many of the people who became Christians would have been slaves. These relationships were one of the surprising things about the New Testament church. Individuals who were typically separated in society could be found in a vibrant community that loved each other which served as an apologetic for the church and God. The question was, "What were they to do now that they were free in Christ?" The answer was that they were to live in such a way that the name of God would not be reviled, and this was to be accomplished by showing respect to their masters. It seems that some slaves in Christian households had become disrespectful to their masters, and this had resulted in an unacceptable witness. Paul corrects this fallacious reasoning and instructs Timothy to teach them to work even harder so that their brothers would benefit from those who belonged to Jesus and each other. There are principles to apply in the workplace as well. Christians should be the very best employees. They should not be lazy or unreliable because this might undermine the message of the gospel. A Christian should not take advantage of an authority figure at work and expect preferential treatment merely because they are a Christian. The Christian should always work hard because they do all things as unto the Lord and not simply for a paycheck, career advancement, or personal accolades.