Israel’s future is guaranteed based on the existence of the universe. Thus, in the end, for Israel the best is yet to come.
The Church is part of organic Israel, and Israel’s salvation is connected to the fullness of the Gentiles. That means the rapture of the Church will cause Israel to recognize their great error, and the Spirit of grace will be pour upon this nation.
The Gentiles have no hope whatsoever. The future is bleak and the end is total destruction, with no remedy other than escaping to Jesus. Peter writes: “…and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up” (2 Peter 3:10b).