I disagree, but that's besides the point. We're talking about who the elect are. If you trust that Paul knew what he was talking about then that means the elect consist of both Jews and Gentiles who are Christians and not just Jews who are Christians.
Paul did not write Matthew 24:31 And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.
Of course. According to Paul in 1 Thessalonians 4:14-17, the elect (Christians) will be gathered to Christ at the second coming of Christ, which is what is described in Matthew 24:30-31.
So you are saying it comforting for a Christian to know that he must go the great tribulation ?
Matthew 24:31 is about the gathering of the Jews from the nations, a promise that God made to them in Deuteronomy 30:1-6. The gathering of the house of Israel when Jesus has returned is also in Ezekiel 39:28.
Deuteronomy 30:
1 And it shall come to pass, when all these things are come upon thee, the blessing and the curse, which I have set before thee, and thou shalt call
them to mind among all the nations, whither the LORD thy God hath driven thee,
2 And shalt return unto the LORD thy God, and shalt obey his voice according to all that I command thee this day, thou and thy children, with all thine heart, and with all thy soul;
3 That then the LORD thy God will turn thy captivity, and have compassion upon thee, and will return and gather thee from all the nations, whither the LORD thy God hath scattered thee.
4
If any of thine be driven out unto the outmost parts of heaven, from thence will the LORD thy God gather thee, and from thence will he fetch thee:
5 And the LORD thy God will bring thee into the land which thy fathers possessed, and thou shalt possess it; and he will do thee good, and multiply thee above thy fathers.
6 And the LORD thy God will circumcise thine heart, and the heart of thy seed, to love the LORD thy God with all thine heart, and with all thy soul, that thou mayest live.