By Dr. Tony Garland
Q. In the Old Testament, the terms "Israel," "Jacob," and "Jew" all seem to clearly be applied to the grandson of Abraham, the son of Isaac, the man Jacob and his physical descendants (Gen. 32:28; 35:10). But in the New Testament, the terms "Israel" and "Jew" are used in passages which are more difficult to understand which some interpret as teaching that faithful Gentiles are described as "Israel" or "true Jews" (e.g., Rom. 2:28-29; 9:4; Gal. 6:16). Can you shed some light on this?
A. I believe that much of the confusion concerning the use of the term "Israel" in the New Testament—and especially whether it refers to believing Gentiles—can be cleared away by recognizing that although, consistent with its use in the Old Testament, the term always denotes those who are physical descendants of the man Jacob, there are also passages where the writer desires to call attention to a subset from within the physical descendants of Jacob who also share the faith of father Abraham. Here are some principles to consider when reading such passages:
- The unbelieving descendants of Jacob are said to be "not Israel" (e.g., Rom. 9:6) and are described by Jesus as those who “say they are Jews, but are not” (Rev. 2:9; 3:9). In other words, true Israel consists of true Jews who, like Paul, are both physical descendants of Jacob and share the faith of Abraham (Luke 3:8). The unbelieving descendants, by rejecting the faith of their physical father Abraham, are said to have a different father - the devil (John 8:39-44; Rev. 2:9; 3:9).
- Even though unbelieving descendants of Jacob are sometimes referred to as those who “say they are Jews, but are not, but lie” (Rev. 3:9), there are other passages in which the term “Israel” is clearly applied to the same group of unbelieving Jews (e.g., Rom. 9:6,31; 10:1,21; 11:7,25-29). Thus, what is being stressed is that the physical descendants of Jacob who reject the faith of Abraham are not fulfilling their true intended position of being both physical descendants and believers. The New Testament writers are careful, when necessary, to differentiate the entire nation of physical descendants (which includes non-believers) from the elect remnant which believe.  While some passages emphasize this truth when making a specific point, we must take care to realize many other passages equally assert that the unbelieving descendants of Jacob are still “Israel” and “Jews.”
- Passages which are distinguishing between a true Jew (of faith) and those who are merely physical descendants but lack faith never refer to Gentiles as “Jews” or “Israel.” The distinction which is being made is between believing descendants of Jacob and unbelieving descendants of Jacob - but in both cases descendants of Jacob. This becomes evident when one is careful to consider the context and logic involved in the passages. For example, “They are not all Israel who are of Israel” (Rom. 9:6). Someone who has formal training in logic will recognize this statement as describing a strict superset/subset relationship. Two groups are involved with one group being strictly contained entirely within the other. The superset are those “who are of Israel” - the physical descendants of the man Jacob. The subset from within that group are those who “are not . . . Israel”—the unbelieving physical descendants of the man Jacob who the Scriptures elsewhere indicate are not true Jews (Rom. 2:28-29; Rev. 2:9; 3:9). A pictorial aid known as a Venn diagram can be helpful here. In this particular case, the diagram will consist of two concentric circles, much like a donut or - more appropriately considering the subject at hand—a bagel! The outer circle of the bagel surrounds everyone born in the physical line of descent from Jacob. The inner circle of the bagel surrounds those who have been born in the physical line of descent from Jacob, but who also believe in Jesus as Messiah. The region between the two, in red, represents “not all Israel”—unbelieving Jews—whereas the region in green represents believing Jews who are elsewhere called “the Israel of God” (Gal. 6:16).
A key distinction which must be kept in mind is to notice that the New Testament never refers to Gentile believers as the seed of Isaac or children of Jacob. Instead, “those who are of faith are sons of Abraham” (Gal 3:7-9,29). This is because we Gentiles who believe participate in the unconditional promise which God gave to Abraham, “In you all the families of the earth shall be blessed” (Gen. 12:3 cf. Gal. 3:8). The way in which the Gentiles participate in this promise is through their identification with Abraham’s descendant Jesus, having believed upon Him by faith. Instead of being sons of Isaac or sons of Jacob, our relationship as Gentiles to the New Covenant goes back to its very source in the promises given to Abraham who is called the “father of all those who believe” (Rom. 4:11)—both believing Jews and believing Gentiles (Luke 19:9; Rom. 4:11-18). This is the root of the cultivated olive tree into which believing Gentiles have been grafted and unbelieving Jews have been cut off (Rom. 11:16-18). 
After warning the church of Philippi concerning unbelieving Jews, where Paul is emphasizing that true circumcision is of the heart, the most he will say is “we are the circumcision, who worship God in the Spirit, rejoice in Christ Jesus, and have no confidence in the flesh”. Thus Paul contrasts spiritual circumcision of the heart by faith with physical circumcision, an external rite which in and of itself does not produce saving faith. If there was ever a passage where Paul could clearly redefine Israel to mean believing Gentiles this is it, yet he does not go that far. Even here, Paul is not really teaching anything new because this theme is strongly taught within the Old Testament (e.g., Deu. 10:16; 30:6; Ps. 119:70; Jer. 4:4; 9:26; Eze. 36:26; 44:7).
- What this means is that the larger circle (superset)—the outer rim of the “bagel”—which also circumscribes the inner circle (subset) encircles people who are all physical descendants of Jacob and contains not a single Gentile, believing or otherwise.
- Passages which distinguish between believing Jews and unbelieving Jews are placed around the concentric circles with arrows pointing to which of the two groups are in view: 1) the Jewish believing remnant represented by the center green region; 2) the unbelieving Jews who are not “true Jews” in the outer red region.
- A third yellow circle, below the two concentric circles, shows the position of believing Gentiles who are “sons of Abraham by faith” but also still called “Gentiles” and never Jews.
- The rest of the diagram, the region outside the circles (or background as it were), can be thought of as containing unbelievers who are neither the physical descendants of Jacob nor share the faith of Abraham. These, together with the Jews in the red region, are lost having never trusted in the ultimate representative of true Israel: Jesus Christ.
I hope this helps to clarify the way in which the New Testament addresses the issue of physical descendants of Israel verses Gentiles who are children of Abraham by faith—but still Gentiles (Gal. 2:12,14; Eph. 3:6).
 Concerning the believing remnant, see 1Ki 19:18; 2Ki 19:4; 2Ki 19:30; 2Ki 21:14; 2Ki 25:22; Ezr 9:8; Ezr 9:15; Isa 1:9; Isa 6:13; Isa 7:3; Isa 10:20-22; Isa 28:5; Isa 37:4; Isa 37:31-32; Isa 46:3; Isa 59:21; Isa 65:8; Jer 5:10; Jer 5:18; Jer 23:3; Jer 44:28; Jer 50:20; Eze 5:3; Eze 5:12; Eze 6:8-10; Eze 9:8; Eze 9:11; Eze 11:13-16; Eze 12:6; Eze 14:22; Joe 2:32; Mic 2:12; Mic 5:7-8; Mic 7:18; Zec 11:10; Zec 13:8-9; Ro 9:6; Ro 9:27; Ro 11:5; Ro 11:17; Ro 11:25; Ga 6:16; 1Pe 1:1; Re 12:17
 A common error in interpreting this passage is to mistake the cultivated olive tree with its root as denoting Israel such that believing Gentiles are joined to Israel. But the root concerns the promises made to Abraham as the father of the faithful. Also, unbelieving Jews who are called “Israel” in this passage are broken off from the tree with its root. Thus, the tree and its root cannot be Israel.