We can't just say "Israel" and know who we're talking about. There are three distinct groups of Israelites in the eyes of God, and these are those who will endure the Tribulation:
1) The Remnant. These are described by Paul in Romans 11 as faithful to the promises God gave to Abraham. They are NOT a part of the general apostasy.
2) Nominal Christians with no true spiritual leanings; part of the Lost Ten Tribes
3) Nominal Christians with spiritual leanings; part of the Lost Ten Tribes
These groups ought to be distinguished from members of the body of Christ.
There could be a fourth category of Israelites here, namely those of the chosen nation
who have forsaken their national identity to embrace Paul's gospel. Paul himself would be Exhibit A of this group. I have excluded these as a group because they will NOT go through the Tribulation, but will be snatched away beforehand.
The Tribulation affects each of the groups differently. The Remnant can be broken down into 1) the 144 thousand, 2) the
"vast throng" of Revelation 7:9, and 3) those who are are faithful yet un-sealed, many of whom will die with honor as martyrs. The Remnant do astonishing things for God, faith-wise, in the heat of The Tribulation.
The second group, nominal Christians (part of the Lost Ten Tribes) with no spiritual inclinations—those who go to church and like being
called "Christians" only because it's a popularity club and a good way to virtue signal—these will be hardened by the Tribulation and will curse God to His face. They never were true believers, and now they can drop all pretensions. These will readily join the Beast system.
The third group, nominal Christians (part of the Lost Ten Tribes) with spiritual
inclinations, these will be shaken from their spiritual malaise by the Tribulation, rising to the occasion. They may, indeed, become part of "the vast throng" of Revelation 7:9. They will be spiritually awakened to their Israelite identity and will receive the New Covenant spirit (they will receive understanding) just as the disciples did in the upper room.
