1Ti 6:1 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.
Ask yourself, do you we mind being called a servant as long as you are not treated as one? Paul in this verse addresses workers/servants as people under yoke, under governing authority. If you are a servant/slave, you must honor and glorify Christ by being respectful and obedient to Christian and non Christian masters that the true teaching of Christ may be displayed and not blasphemed. The exhortation is natural as there is a danger of Christian slaves inwardly feeling above their heathen masters.
Service rendered for the love of God must not be inferior to that rendered for fear of man. God was with Joseph when he served heathen masters, and even God blessed them because of Joseph, and they too recognized God’s working through him. Our work ethics is a true reflection of the heaven we represent. Mat 5:16 “…let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven.”