For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek. — Rom 1:16 (kjv)
he’s not ashamed - he holds the Gospel in such high regard that no one can make him feel subpar about his belief in it. It trumps all of mans’ opinions. The gospel is the thing that he is fixated on.
for it is the power of God unto salvation - he isn’t ashamed because he knows that the thing he believes in is rooted in the power of God, the supreme being who created all. God birthed it. God maintains it. God fulfills it. Man cannot do anything to disrupt the salvation that God has provided, so Paul can raise the banner and proclaim the word with confidence, because it is backed by the power of God.
to everyone that believeth - God doesn’t discriminate who he offers salvation to. EVERY ONE means everyone. no matter your background. no matter your previous beliefs. no matter your past. God’s power trumps all of the sin and false beliefs we may have held.
to the Jew first and also the Greek - reading in the context of the time that Paul wrote this, Jesus first came to the Jews, but they rejected him and crucified him. God always had a plan to open the gospel to everyone, as the Scripture says.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. — john 3:16 (kjv)
“But do not overlook this one fact, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slow to fulfill his promise as some count slowness, but is patient toward you, not wishing that any should perish, but that all should reach repentance.” (2 Peter 3:8-9 kjv)
God used the sin of the Jews (their rejection and crucifixion of Jesus) as an opportunity to open the door to the Greeks (aka the Gentiles, aka everyone who wasn’t Jews)
For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith. — Romans 1:17 (kjv)
for therein is the righteousness of God revealed from faith to faith - What is** faith to faith?** That means the relationship with Jesus begins from a place of faith (we can’t know everything here on earth, so we must trust Him and believe on His words), and it continues from a place of faith. Every day we have to exhibit faith in Jesus and His Word, because we will come in contact with new situations and scenarios that we don’t understand with our own human knowledge. We have to keep taking it back to Him in prayer, trusting that He will lead and guide us.
the just shall live by faith - Paul is actually quoting
Behold, his soul which is lifted up is not upright in him: but the just shall live by his faith. — Habakkuk 2:4 (kjv)
This shows that Paul valued the writings of the Old Testament. Remember, Paul was once Saul, a prominent Pharisee. So he studied and understood much of the old Testament because of that. In Habakkuk 1 and 2, Habakkuk is talking with the Lord about the fact that the law is slack and the wicked are not being held accountable (Hab 1:4). He notes that the Chaldeans will be used by the Lord for judgement. (Hab 1:12) . Even in that time of trial, the just (those who are lawful and righteous) had to continually live by faith that God knew what he was doing.
We have to do the same today when faced with the influence and impact of wicked men and sin.
For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; — Romans 1:18 (kjv)
men who hold the truth in unrighteousness - These men have a glimpse of the truth. They understand it on some level. However, they “hold” (keep in their memory) the truth, modifying it by looking at it through a lens of unrighteousness. They don’t want to see the truth for what it, righteous and complete. So they modify it to fit their sinful worldview.
God continues to reveal his wrath against those who would pervert his Word. He is patient, calling all to repentance, but we see through past history where those cultures and empires and states who have gone against God have eventually become no more. Amalekites, Hizzites, Chaldeans, Nazis, Aztecs, Romans, etc. People groups, religions, and all who stand against the truth of Christ eventually fall.
Because that which may be known of God is manifest in them; for God hath shewed it unto them. — Romans 1:19 (kjv)
God shows the truth to all in the truth of His word in the Bible. It is our decision to accept it in its entirety or reject it in its entirety. God has shown us all we need to know. We cannot believe some and reject some. The purest tank of water, when tainted with a single drop of poison, becomes completely impure in it’s entirety. There is no way to say that the Bible contains both truth and lies. It’s all or none. If it’s all truth, then that means that anything that comes after it that contradicts it must be lie.
For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: — Romans 1:20 (kjv)
Humanity is included in “the things that are made”. God created us, and we all have an internal understanding that there is someone that created us for a purpose. That is why all of humanity searches for meaning and purpose in something, whether it be the true God, false gods, or self. We all recognize that need for something more. When God reveals himself to us through his word in the Bible, we are then without excuse. We will not be able to stand before the Lord one day and say “God I didn’t know”
Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. — Romans 1:21 (kjv)
When God has revealed himself to us through his word in the Bible, and we still refuse to bow and acknowledge Him for who He is, then we are foolish. We become vain in our imagination. We make up new rules, new revelation, and new processes to mask the underlying issue… we don’t believe the revelation God has already established and given. We begin to imagine and make up extra things. Contradictory things. In doing so, the heart that should be focused and committed to the Lord becomes darkened and foolish, turned away from Him.