I believe I *have* supplied scriptural support in past posts (perhaps even in this thread, not sure).
Revelation 1:1 states, "The Revelation of Jesus Christ WHICH GOD GAVE UNTO HIM [Jesus] TO SHEW UNTO His servants [see Rev7:3 the 144000 "servants of our God"] things which must come to pass [<--compare 4:1's phrasing, re: the FUTURE aspects of the Book] IN QUICKNESS [NOUN]…" NOT things which will transpire over the course of some 2000 years (i.e. not "FROM the first century"), but "IN QUICKNESS [NOUN]" (parallel phrase to that found in Lk18:8 re: "avenge" [see Lk17-end context as well]; and parallel also to Rom16:20 [re: "the Church which is His body's" role, during that same future specific limited time frame, different location (1Cor6:3[14]; etc)]). Much more, but this is sufficient for now.
Note how the 144,000 (singular nation) is set in contradistinction to the "a great multitude... of all the nations [plural]" in Rev7. They are kept distinct BECAUSE they are not of "the Church which is His body" (wherein there is NO distinction, in our standing before God "IN Christ") though they are indeed "saints" (having come to faith IN/DURING the trib years [AFTER our Rapture]).
[Note and apply ('correctly apportion') the three distinct: "the Jews," "the Gentiles," "the Church of God"]
Isaiah 60 (your other passage) also shows them to be distinct.
Here is a quote by William Kelly, to that point:
[quoting]
"But in our chapter [Isa60] Jerusalem has its proper central place, as the metropolis of the earth when all shall be settled and governed according to God. Nor is it only sons and daughters that thus come to Zion from far, but strangers too. For there is then to be no such state of things on earth as the church of God, one body, Christ's body. On the contrary Gentiles and Israel, though both blessed by Jehovah, will be distinct and kept so, however harmonious in their relations." --Wm Kelly, Commentary on Isaiah 60 (from Bible Hub)
Note that the Matthew 24:29-31 gathering is parallel with Isaiah 27:12-13 where Israel will be gathered [AFTER/AT END of the trib] "ONE by ONE" (in CONTRAST to our Rapture, which will be "AS ONE" [the "ONE BODY"])