As with most of Paul's letters the first chapter starts out with a greeting. Like most of his greetings, you can gain some insight from them. For example in this greeting he mentions Jesus' human nature, and that He is the Son of God. He also talks about the "obedience that comes from faith" in verse 5.
This 'obedience that comes from faith' is important, since one of the most prevalent doctrines today, OSAS (once saved always saved) states that even if you don't continue in the faith and even if you have never been obedient or followed Christ you are still saved. Paul states here that true faith will be accompanied by obedience.
Paul then also speaks about a righteousness that is by faith in verse 17. Again obedience and righteousness come from our faith. If you aren't righteous and aren't obedient, then you better question whether you truly have saving faith. None of this means that we can't and don't stumble and fall at times, but if our lives are not characterized by obedience and righteousness then there is a problem.
In verse 18 Paul starts to talk about those who have rejected God's righteousness. People claim there is no evidence for God, yet Paul tells us that His eternal power and divine nature are plain to see and understand if people will not reject it. They condemn themselves.
He also goes on to mention what happens when people reject the truth; they are given over to their lusts.
Paul does not mention homosexuality by name here, but it is obvious to anyone willing to read this passage that this is what he is speaking about.
Because of this, God gave them over to shameful lusts. Even their women exchanged natural relations for unnatural ones.  In the same way the men also abandoned natural relations with women and were inflamed with lust for one another. Men committed indecent acts with other men, and received in themselves the due penalty for their perversion.
He goes on to mention many other sins that are caused by the rejection of God. He mentions many things: They have become filled with every kind of wickedness, evil, greed and depravity, envy, murder, strife, deceit and malice, gossips, slanderers, God-haters, insolent, arrogant and boastful; they invent ways of doing evil; they disobey their parents; senseless, faithless, heartless, and ruthless.
After listing all those things in chapter 1 that people who reject the truth do that are sinful, Paul then brings the thought home to those who do the same things but claim to be believers. In verse 1 of chapter 2 he tell them that they have no excuse; they pass judgment on the world for the sinful things they do and yet they do the same things. He asks how they think they will escape God's judgment.
Again this is a dagger in the heart of the OSAS doctrine, which does claim that sinful man will be punished in hell, but that a believer can do the very same things with immunity. Paul tells us that there is no excuse in such thinking and that we won't escape God's judgment for our sins, if we continue to sin in this way.
But because of your stubbornness and your unrepentant heart, you are storing up wrath against yourself for the day of God's wrath, when his righteous judgment will be revealed.
To those who by persistence in doing good seek glory, honor and immortality, he will give eternal life.  But for those who are self-seeking and who reject the truth and follow evil, there will be wrath and anger.
Don't be fooled by these false doctrines, we must follow Christ and we must repent and discontinue our sinful ways; that is what salvation is, a turning from our sinful past and living a righteous life by grace through our faith in Christ.
Paul then goes into the Law, where he explains that the Law does not save, and that those who brag on having the Law are just fooling themselves because they sin just like the gentiles who don't have the Law, and in fact God has put a law into man's heart so that some gentiles follow it, and that God will judge all men by the law His has placed in every person's heart.
The Jews often looked down on gentiles, who they claimed were just sinners, but Paul is saying that they condemn themselves also because they brag about the Law and yet don't follow it, they sin too.
He then goes on to say that not all Jews are Jews because of birth, but rather they are Jews (descendants of Abraham) because of faith.
to be continued...
Mail Ralph Dettwiler