In Christ all of us Christians are equal. Before the world there must remain an inequality according to which the father is more than the son, the master more than the servant, a king and a prince more than their subjects. God...has established and created stations of life in this way. Now granted that the inequalities in the world are as great as possible, we should find comfort in the consideration that, no matter how high or low our station may be, we all have one Christ, one Baptism, one Gospel, and one Spirit, and that no one has a better Christ than the most insignificant maid and the most insignifcant servant. For even though another may have more money, property, and other things than you have, he does not for this reason have another or a better God.
This we should learn and carefully note, that everybody may heartily and gladly serve God in his station in life...
Now he who enjoys these possessions and knows that we are all equal in Christ goes about his work with delight and is not concerned even though for this short time here on earth he is in more modest circumstances and in a lowlier position than another.
what Luther Says - para 4255 - p. 1324