I have been searching around in the context trying to find the answer to this question. It does not seem clear at first just what the real advantages are other than being entrusted with the oracles of God. And even then, why is that an advantage? And then there is that word “first” which doesn't seem to ever have a “second” afterwards. It seems that Paul gets sidetracked permanently and goes off on other subjects without finishing what he started here. But I'm not sure that is the case necessarily. It is more likely that I am not scrutinizing the text carefully enough and thinking broadly enough to capture a clear picture of what he is trying to get across.
So I scanned over the following verses and chapters with the question in mind, “what advantage has the Jew?” I do remember that quite often Paul will mention the sequence “to the Jew first and also to the Greek”. That too has always raised a question in my mind.
I am sure I do not have the complete answer right now but I am starting to see some possibilities. Chapter 3 seems to be a warning that the “advantages” that the Jews thought they had are in fact not the true advantages that God really gave them. They were very much into boasting about their exclusiveness, their ancestry and their supposed “corner on God” mentality. They had become very dependent on their knowledge of religion, the Law and God's requirements while ignoring issues of their heart. They believed, as many of us still do without realizing it, that at least to some extent their salvation depended on some level of performance to leverage God to save them, whatever “save” meant in their minds. So the “advantage” that they thought they had over the rest of the non-Jewish world was that they had the right information as well as the right ancestors and consequently believed that God considered them more valuable than any other people.
The whole book of Romans works to disassemble these assumptions and uncover God's true reasons for using the Jews as His chosen people. The same principles apply to anyone today who mistakenly believes that their church affiliation, their religious upbringing or their extensive knowledge of what they believe to be irrefutable truth from the Bible gives them an advantage over others by impressing God and influencing His view of their value. Of course this is often done at the subconscious level until it becomes so pervasive that it spills into the open as boasting and bigotry toward others.
These are the things that Paul is trying to undo in their minds as “advantages”. But what are the true advantages that the Jews had? We have already seen that the first advantage he lists is the fact that God entrusted them with His oracles. Even here we must be careful to pay attention to what the advantage really is. It is not so much the oracles that are the advantage, though that is part of it, but it is the fact that God entrusted them, that He showed faith in them, that was the real blessing and advantage.
According to verse 4 God is going to be judged as to the wisdom of trusting people, having faith in people who end up not believing the very things that He revealed to them about Himself and responding positively to them. Evidently God's faithfulness is His choice to trust that people He entrusts will respond to His faith in them by believing Him. And when they fail to believe or respond as He had hoped His own credibility is then called into question. His credibility is really what is termed His “righteousness” or His being correct in the choices He makes.
So if their first advantage is that God had faith in them, whether or not they responded positively to His faith by believing and having faith in Him, what else could be seen as an advantage? The “first of all” phrase implies that there is more here than just being entrusted as an advantage.
As I scan over the surrounding passages I think I might be starting to perceive what the real advantage might be. In chapter 4 Paul presents the story of Abraham as a person who understood his advantages correctly and was not sidetracked by the delusions of the current Jews about the nature of their advantages. Abraham also received “oracles” from God, promises and insights and communications directly from God that were not given to others in his day. But Abraham did not respond by boasting in his superior knowledge or his apparent favored position with God by trusting in those things for his inner value or his standing with God. Abraham responded from his heart by acting in faith in response to God's faith in him. Abraham did not believe that the works he did, the obedience that he displayed to do what God asked him to do was the reason for God to bless him. He simply believed in the true character of Who God really is and what He is like and responded by reflecting God's faith and love back to Him. In so doing He received even more blessings and revelations and advantages and his belief in God's goodness, apart from his actions, was declared by God to be “righteousness” in God's eyes.
This is where things can get real tricky. It is very easy to slip into the idea that this “righteousness” of Abraham became the reason God valued him or somehow changed God's view of him. It is very easy to assume that this righteousness somehow contained merit that gave Abraham an advantage over other people. In fact that is the very issue that the Jews were so hung up on because they believed that by merit of genealogy their connection to Abraham gave them an inside track on God's favor. But isn't that true in all ages? We often seem to have this penchant for depending on supposed merit that is somehow transferable through associations or relationships with others that we believe have achieved an inside advantage with God. It is the way we operate in politics and so we assume that it works with God too.
Paul makes a strong case that the advantages of the Jew is not in their connection with Abraham or any other “saint” and their advantage is not because of their ability to perform the requirements of the Law. But again, what is the advantage? What, besides the fact that they were “entrusted”, gave them advantages over the rest of the world? Why did Paul say in 1:16 that the gospel is the power of God for salvation to...the Jew first?
Though I do not see it spelled out explicitly in this passage, I think I may be beginning to perceive what the real advantage might be. It has to do with the primary instruction Jesus gave to His disciples when He commissioned them to take the good news about God to the whole world. Their number one job description and identity was to be witnesses. A witness is a person who reports first-hand information about something or someone that they know and have experienced personally. Since the whole Great Controversy revolves around false charges against God and the eventual vindication of His choices and His character, He has asked His disciples to be witnesses for Him to testify on His behalf as to what they know and have personally experienced in their relationship with Him.
Given that context, who would have the greater advantage and carry more weight as an effective witness, someone who had just come to know about God, about His ways and wisdom and how He relates to His children, or someone who had received extensive knowledge and insights and was much more familiar over a longer period of time with God's dealings with men? Even in our corrupt judicial system we realize that a person who knows very little about someone else and has only recently come to know them personally does not carry nearly as much credibility with a jury as one who is intimately acquainted with the accused and has had a long and close connection with them.
And speaking of advantages, who is the advantage really benefiting anyway? Are our advantages given to us to make us boast about our superior knowledge and our “inside connections” with the God of the universe, or are our advantages really given to us for God's benefit that He may be justified in His words and prevail when He is judged (3:4)?
Thus said Jehovah: Let not the wise boast himself in his wisdom, nor let the mighty boast himself in his might, let not the rich boast himself in his riches, but – in this let the boaster boast himself, in understanding and knowing Me, for I am Jehovah, doing kindness, judgment, and righteousness, in the earth, for in these I have delighted, an affirmation of Jehovah. (Jeremiah 9:23-24 YLT)