Old Testament quotations in Rom 10:6-8

The Old Testament quotations in Romans 10:6-8 are much tougher to make sense of. The text is:

Rom 10:6 But the righteousness based on faith speaks as follows: "DO NOT SAY IN YOUR HEART, 'WHO WILL ASCEND INTO HEAVEN?' (that is, to bring Christ down),
Rom 10:7 or 'WHO WILL DESCEND INTO THE ABYSS?' (that is, to bring Christ up from the dead)."
Rom 10:8 But what does it say? "THE WORD IS NEAR YOU, IN YOUR MOUTH AND IN YOUR HEART"--that is, the word of faith which we are preaching,

These are quotation from Deut.:

Deu 30:10 if you obey the LORD your God to keep His commandments and His statutes which are written in this book of the law, if you turn to the LORD your God with all your heart and soul.
Deu 30:11 "For this commandment which I command you today is not too difficult for you, nor is it out of reach.
Deu 30:12 "It is not in heaven, that you should say, 'Who will go up to heaven for us to get it for us and make us hear it, that we may observe it?'
Deu 30:13 "Nor is it beyond the sea, that you should say, 'Who will cross the sea for us to get it for us and make us hear it, that we may observe it?'
Deu 30:14 "But the word is very near you, in your mouth and in your heart, that you may observe it.

The first issue here seems to be finding the connection between what Moses wrote and what Paul wrote. Rom 10:6 is a quote of Deut 30:12 with Paul adding the phrase "(that is, to bring Christ down)". There seems to be nothing in Deut to indicate that Christ was any part of this commandment. This seems to also be the same issue with the next part.

The commandment that Moses is giving is to observe all the Law. The spirit of what Moses is saying is that a person has to turn to God with all their heart and soul. The commandment is not out of reach but was given to them. It was incarnated in the Law. The commandment is not in heaven, but it right before them. This does reflect the idea of the mission of the prophet. The prophet took the words of God and made the people listen to God. This is the same notion as in the next verse which it also contains the phrase "and make us hear it". It doesn't take a trip into Heaven or across the sea to get the answer. The answer is right there in the commandment.

Paul's quotation of Deut 30:13 seems to be problematic as well. The point there is about "across the sea" and yet Paul's quotation is about "the abyss". This may be resolved by examining the Septuagint.

What does match well is the sense of the passage that follows in both the Deut and Romans texts. Paul is laying before them an option of either following or rejecting Christ. That is exactly what Deut 30:15-20 does as well.

Deu 30:15 "See, I have set before you today life and prosperity, and death and adversity;
Deu 30:16 in that I command you today to love the LORD your God, to walk in His ways and to keep His commandments and His statutes and His judgments, that you may live and multiply, and that the LORD your God may bless you in the land where you are entering to possess it.
Deu 30:17 "But if your heart turns away and you will not obey, but are drawn away and worship other gods and serve them,
Deu 30:18 I declare to you today that you shall surely perish. You will not prolong your days in the land where you are crossing the Jordan to enter and possess it.
Deu 30:19 "I call heaven and earth to witness against you today, that I have set before you life and death, the blessing and the curse. So choose life in order that you may live, you and your descendants,
Deu 30:20 by loving the LORD your God, by obeying His voice, and by holding fast to Him; for this is your life and the length of your days, that you may live in the land which the LORD swore to your fathers, to Abraham, Isaac, and Jacob, to give them."

The key issue here seems to be that of a choice. The way of God is to follow Jesus Christ and live. The alternative is death. In the Old Testament the choice was physical life and safety or death and destruction. In the New Testament the choice is between eternal life and death.

Any thoughts in what Paul is doing here are appreciated. This is an obscure point to figure out.