I ask then, did God reject his people? May it never be! For I also am an Israelite, a descendant of Abraham, of the tribe of Benjamin. Romans 11:1

The question the whole chapter hangs on is stated ahead of everything else in the chapter: "..did God reject his people?" By saying "I also am an Israelite, a descendant of Abraham, of the tribe of Benjamin" Paul is defining whom he means by "His people." He means Israelites descended from Abraham, including his own tribe of Benjamin. All Israel is in view here, not just the Jews. Therefore, the question under consideration is, "has God rejected Israel?"

That Israel as a whole is in view here is consistent with the example Paul uses next:

God didn’t reject his people, which he foreknew. Or don’t you know what the Scripture says about Elijah? How he pleads with God against Israel: Lord, they have killed your prophets, they have broken down your altars; and I am left alone, and they seek my life.” But how does God answer him? “I have reserved for myself seven thousand men, who have not bowed the knee to Baal.” Even so then at this present time also there is a remnant according to the election of grace. Rom 11:2-5

This example given by Paul is consistent with his opening comments. Here, Paul uses the ministry of Elijah as an example. Elijah principally is known for prophesying to the northern 10 tribe kingdom of Israel, again cuing us in to the real question Paul is addressing, i.e., "did God reject His people," meaning all Israel. The example Paul has chosen shows that Elijah was not really alone. In his day a remnant of Israel had been reserved by YHWH. After noting this Paul states "at this present time also there is a remnant" - meaning a remnant of all Israel.

The central point of the whole argument is thus well defined: Paul is answering the question of whether natural Israel as a whole has been rejected. This is not just the Jews. Now that Paul has made this fundamental point that a remnant of Israel was then, in fact, in view, Paul asks the next question.

What then? That which Israel seeks for, that he didn’t obtain, but the chosen ones obtained it, and the rest were hardened. Rom 11:7

"He" here applied to Israel must refer to Jacob as personified in the whole of Israel! The "chosen ones" here, in context, must be the believing remnant of Israel that Paul had just mentioned. No dichotomy between the two houses of Israel is made here. Rather, the dichotomy is defined here as between the believing remnant of Israel, the "chosen ones" and "the rest" who were "hardened." This can only be all the rest of Israel that had not believed. That a remnant of Israel remains proves that Israel is not rejected. This leaves us to consider the rest of Israel that have not believed. After appealing to prophecy, Paul introduces the next question about unbelieving Israel:

"I ask then, did they stumble that they might fall? May it never be! But by their fall salvation has come to the Gentiles, to provoke them to jealousy." Rom 11:11

No change in the context can be identified up to this point. "They" is still referring to all the unbelieving Israelites of all the tribes. There is nothing here to indicate Paul has switched gears and is now speaking of the Jews only in asking this question; "did they stumble that they might fall?". Since this question has in view all unbelieving Israel, then the "Gentiles" Paul next introduces into the discussion cannot be the exact same people! On the contrary, "Gentiles" here must be such in the ordinary sense of the word. Here, Gentiles are worldlings of the 70 nations. The failure of the majority of Israel to believe has opened the door of salvation to the world, to all people everywhere. That is the thrust of Paul's argument.

Consistent with all of this, when Paul goes on to say "some of the branches were broken off" the branches he refers to are natural Israelite branches, inclusive of branches from all tribes of Israel. "Grafted in branches," following the line of logic already established by Paul, must therefore be Gentile believers who, though not being natural branches (natural Israelites) are still grafted into Israel's olive tree by faith. "By their unbelief they (unbelieving Israelites) were broken off, and you (believing Gentiles) stand by your faith" Paul says.

All of this has been to demonstrate that "natural branches" in Romans 11 are Israelites of every tribe, not just the Jews. With this point shown from context, let's consider the word translated as "natural."

Natural - G5449 - phusis - foo'-sis

From G5453; growth ..(by implication) natural production (lineal descent); by extension a genus or sort; figuratively native disposition, constitution or usage.