Who are these gathered from the nations after the tribulation of those days?
They are the surviving mortals of the gentile nations who will be gathered and separated according to their behavior with regard to Israel during the tribulation period
Those who become believers [the sheep] during the tribulation period will be aware of and sympathetic to the believing remnant part of Israel [the Lord’s brethren; His kin]
This gathering is not a resurrection to immortality and none of these are of the Lord's church of today
The Lord will separate the believing sheep from the unbelieving goats and the sheep of the nations will enter and populate His millennial kingdom as mortals, the goats will be rejected
Here is the proof text from scripture [
Matthew 25:31-46;
Revelation 20:1-3]