Romans 9:5 may be the biggest controversy in the Greek New Testament. Many say that it affirms the deity of Jesus, while others say it doesn't. It can be translated many ways to begin with, but when you add the fact that Koine Greek was written 2000 years ago in all capital letters, with no spaces, no punctuation, and no accent marks, it becomes an even larger problem.
Here’s the passage in today’s accented koine greek.
ὧν οἱ πατέρες, καὶ ἐξ ὧν ὁ Χριστὸς τὸ κατὰ σάρκα: ὁ ὢν ἐπὶ πάντων θεὸς εὐλογητὸς εἰς τοὺς αἰῶνας, ἀμήν.
of whom are the fathers, and from whom is the Christ according to the flesh [decent], who is over all. God be blessed forever! Amen.
of whom are the fathers, and from whom is the Christ according to the flesh [decent]. Who is, while being over all, the blessed God forever. Amen.
of whom are the fathers, and from whom is the Christ according to the flesh [decent], who is God over all, blessed forever. Amen.
or...just check your favorite translation.
Here’s an analysis on the accented greek.
ὧν is a relative pronoun which in this form is plural. In this passage, it is referring to the Jews of whom Jesus is from according to decent.
ὢν is a present participle of “I am” [don’t confuse it with ὧν! Note the accents and breathing marks]. It can be translated “is” or “while being”. It carries a continuous aspect.
Both θεὸς and εὐλογητὸς are in the nominative case and are both nouns [εὐλογητὸς is actually an adjective, but it is functioning as a noun here *my opinion]. In most cases, a “to be” verb is inferred. God be blessed forever!
This view is supported in some translations, but not all. Take a look at the footnotes on the NIV passage.
I will be the first to admit that this is a hard passage to translate. Think of this: the original was in all capital letters, with no spaces, no punctuation, and no accents. This is how it would have looked. I’ve highlighted ΩΝ (ὧν or ὢν).
So what happens when no one is really sure of how ΩΝ should be accented? One’s theology comes into play. My Greek teacher once said that you can discover a person’s theology based on how he translates the Greek. The truth is that no one really knows what Paul meant in this passage except Paul and God. This is one that you have to pray over and follow your heart.
When I first started learning Greek, I thought that I would really be able to learn what the New Testament really says. Then this verse comes along. It's just not as simple as that. There's a lot of research on the internet about this passage. I would encourage you to go check it out.