Importance of Old Testament Background and New Testament Context:
To understand the meaning of the 144,000 it is essential to remember that Revelation -- as well as the entire New Testament -- is born in the cradle of Judaism. Figures and numbers used in Revelation have a connection to Old Testament teaching. The first century Christian reader would readily understand that which seems foreign to us at first because of familiarity with OT Scripture of which they had prior to their knowledge of the New Testament corpus.

Also, since Christianity was born in the cradle of Judaism, one would expect a close relationship between the two in Revelation -- and the rest of the New Testament. We saw this relationship in Revelation 12:17: "Then the dragon was enraged at the woman and went off to make war against the rest of her offspring -- those who obey God's commandments and hold to the testimony of Jesus." I would understand that the woman is Israel and "the rest of her offspring" indicates the messianic community -- those who have believed in the "male child" -- Jesus. Therefore, we would expect a close relationship between believing Jews and Gentiles throughout the book of Revelation --and, indeed, throughout the New Testament.

This follows the teaching of Romans 11 in which chapter the believing remnant of Israel remains the natural olive stump -- unbelieving Jews having been broken off -- and believing Gentiles grafted in, i.e., as wild olive shoots. Paul goes on to say natural olive branches, i.e., numerous Jewish believers, will be grafted in after the "full number of the Gentiles has come in," Romans 11:24-26a. This is an event yet to come since the last Gentile is yet to believe, cf. Matthew 24:14.

Although we know God views the Church as comprising both Jews and Gentiles, slaves and free, male and female, Galatians 3:28, we also know He has a special place in his heart for Israel that they might be saved. This is evident in Romans 9:1-5. If anyone ever preached the oneness of all saved people in the Church it was Paul, yet his heart was especially broken for his brothers, those of his own race, the people of Israel, v. 3b. In God's great plan for world evangelism, He knows when that last Gentile will be won to Christ, and He also knows that when that happens there will be a great ingathering of Jews into the Church, Romans 11:25-27. God desires that all might be saved, 2 Peter 3:9, but there is a special concern for His people Israel.

Perhaps this is the reason God revealed to John the marvelous composition of His Church in Revelation being made up of both believing Jews and Gentiles. If the 24 elders are symbolic of believers of all ages, both Jews and Gentiles, (the twelve tribes of Israel and the twelve apostles) this would be a marvelous affirmation of that fact. If the 144,000 is a number symbolizing the complete number of Jews who will be saved -- joining the complete number of saved Gentiles, this would be an affirmation of that fact. If the composition of believing Jews and Gentiles in heaven as symbolized by the Holy City with its twelve gates named for the twelve tribes of Israel and its twelve foundations named for the twelve apostles of the Lamb, this would be a great affirmation of that fact.

Previous Mention of the 144,000:
This is the second time we have come across the 144,000, cf. Revelation 7:1-8. At that time we noted they received the seal of God on their foreheads identifying them as "servants of our God" who belong to Him -- with the result that they are not harmed by the four angels who have the power to harm the land and the sea, i.e., those who execute the wrath of God on earth, cf. Revelation 7:3. (This group is in direct contrast to those who receive the mark/seal of the beast, Revelation 13:16-18; 14:9-13, and who consequently do face the wrath of God on the earth.) Being sealed in order to be spared the wrath of God does not, in my opinion, spare the 144,000 from the wrath of man. I would understand that the 144,000 mentioned in Revelation 7:4-8 are related contextually to the great multitude of tribulation saints mentioned immediately afterward in vv. 9-17 -- perhaps to symbolize the close relationship between Jewish and Gentile believers.

Who Are the 144,000?
Any number of answers have been given to this question by interpreters of Revelation. It is reasonable to assume that the 144,000 found in chapter 14 are the same as those found in chapter 7. They also have God's seal on their foreheads indicating they are identified with Him.

In Revelation 7:1-8, we noted there are discrepancies in the listing of the twelve tribes -- Dan and Ephraim being unnamed. Probably it is because these tribes were especially associated with idolatry -- the idolatry of Dan described in Judges 18 and the idolatry of Ephraim described in 1 Kings 12. Because it is so unnatural to eliminate two of the twelve tribes from the listing found in chapter 7, we may not be dealing with actual numbers of Jewish believers. It may be that God is emphasizing the moral purity and completeness of this group, cf. Revelation 14:4b, 5; 21:27. Note that idolatrous religion is given the figure of the "great prostitute" in Revelation 17. Throughout the Old Testament, prostitution is a figure often used to describe the idolatrous behavior of Israel.

This may also explain the strange expression in Revelation 14:4: "These are those who did not defile themselves with women, for they kept themselves pure." This expression could not refer to normal marital relations since Scripture never refers to the marriage act as a defilement or as something to be shunned. To the contrary, Hebrews 13:4 makes it quite clear that marital relations are honorable and pure. Therefore, it is best to view this expression as emphasizing moral purity when considering the 144,000.

Also, we find the 144,000 are redeemed from the earth and are rejoicing in heaven, Revelation 14:1-3. This fact would lend itself to their connection to the great multitude in Revelation 7:9-17 -- the redeemed who are standing before the Lamb -- those who have come out of the great tribulation.

Further, these 144,000 are described as those having been purchased from among men and offered as firstfruits to God and to the Lamb, Revelation 14:4; cf. 5:8-10. This same phrase, "purchased from among men" in Revelation 5 also refers to the "saints."

Why the number 144,000? Twelve, or multiples thereof, is a number of completeness/fullness in the book of Revelation -- much like the number seven. As was noted earlier, this number may signify the complete number of Jewish believers in the end times -- joining the complete number of saved Gentiles, cf. Romans 11:12, 25-27 -- all of which make up the one Church of Jesus Christ.

Although the early church was very much aware of their oneness in Christ as Jews and Gentiles, they were also very much aware of both groups existing in the Church, cf. Acts chapters 6 and 15. Even today, 2000 years later, we speak of Hebrew Christians in the Church -- not in a discriminatory or separatistic sense -- but noting their continuing tie to the OT people of God. Indeed, there is that unbroken chain of saving faith so eloquently spoken of in Hebrews 11 which carries into today's Church.

Summary:
In the above commentary, we have entered into the relationship of Israel and the Church -- a topic which occupies much of the interchange between Dispensational and Reformed theologians. From my viewpoint, Dispensational scholars tend to create too sharp a distinction between Israel and the Church; but on the other hand, Reformed scholars tend to blur the distinction far too much -- to the point that Israel is the Church -- and vice versa.

As noted above, Romans 11:11-36 is very instructive in order to understand the relationship between Israel and the Church. It preserves the constancy of believing Israel as the natural olive stump even as believing Gentiles are grafted into it -- described as wild olive branches. Consequently, the Church is naturally a beautiful living organism which is both Jewish and Gentile. Israel is not blurred out of existence or swallowed up in the Church. Believing Israel remains an integral part of the Church. Indeed, the Church owes its ongoing life to the nourishing faith it has received and is receiving from the natural olive stump, cf. Hebrews 11. Romans 11:11-36 preserves the necessary balance between Israel and the Church in the study of any NT book -- but especially the study of Revelation as we attempt to understand its symbols and figures in the light of Old Testament truth.