"I don't believe the human race has been transformed to spirit bodies at the second half of the great tribulation. Can you show to me scripture to verify this occurs when the Bride Groom comes for His Bride?"
There are two tribulations. The first is that of the anti-christ, the apostasy. This is the one Christians must be concerned with. It is one of love and peace - all deceit for there shall be famine and that famine is for hearing the word of God (Amos 8:11).
The 2nd tribulation is that of our Father. Jesus comes at the 7th trump, 7th vial and 7th seal.
Mark 13:24. But in those days, after that tribulation,
the sun shall be darkened, and the moon shall not give
her light.
(this is the 2nd tribulation, after that of anti-christ)
25.And the stars of heaven shall fall, and the powers
that are in heaven shall be shaken.
26.And then shall they see the Son of man coming in the
clouds with great power and glory.
27.And then shall He send His angels, and shall gather
together His elect from the four winds, from the
uttermost part of the earth to the uttermost part of
heaven.
"Gather His elect from earth and heaven" - They have not been taken but remain through the apostasy, until he comes at the 7th trump. The elect that are alive and those that have died.
This tribulation should hold no fear for us, for those that remained. God isn't angry at us but loves us. That is when we are changed, in the twinkling of an eye.
1Corinthians 15:
51.Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed.
(those of us that are alive, ALL of us, will be changed)
52.In a moment, in the twinkling of an eye, at the LAST TRUMP; for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
(the last trump is the 7th)
Many will follow him, believing he is Christ (the apostasy).
"That verse is the Bride called out by the Bride Groom. Would you agree to that explanation of the simile?"
Yes, I do agree with you (1 Thess 4:17) is the bride but
that doesn't happen until after Christ, the true Christ, appears.