v1-2 - This chapter opens with an appeal to those under the 'yoke' of slavery, recognizing the burden they're under. Surprisingly, however, Paul doesn't rile them up to protest for their freedom.
Rather, salves are commanded to respect their masters, especially the masters who are members of the church, so that the gospel message of the church will not be compromised.
It seems odd to us that Paul would not more aggressively advocate for the freedom of slaves in Roman society.
The fact that he doesn't is certainly not a back handed endorsement of slavery, but rather a reminder that a person's socio-economic conditions in this world are of little lasting importance.
We live in a society that wants to categorize everyone into either oppressors or oppressed.
This may seem beneficial to the oppressed until it becomes clear that this constant evaluation shreds every ounce of unity between people.
Instead, the Bible announces that Christians find their dignity and self worth in their citizenship in the Kingdom of God, in which all people belong equally to Jesus Christ, regardless of their current station in life (and for the record, the Bible does encourage Christians to improve their lot in this life when possible (Philemon & 1 Corinthians 7:21).
v3-5 - Paul reminds Pastor Timothy not to put up with people who will not agree with sound doctrine.
v6-10 - This passage gives the much needed context to properly understand v1-2.
God wants you not to just blindly obey Him, but He wants you to be content, which is better than being happy (a condition based solely on temporary circumstances).
If you have the basic necessities in life, be content and do not fall into the trap of constantly wanting more.
Having more than others is not wrong, but constantly wanting more than you have is the root of all evil (v10).
With this understanding, we can see that even the poorest slave has an equal (or maybe even better) chance of achieving contentment in life than does the richest aristocrat, which is why Paul gave the advice he did in v1-2.
v11-19 - Anytime you read the words "But you..." in the Bible, be sure to pay attention, because the instruction that follows will be critical for you to understand, especially as culture descends around you.