Although I am not totally certain what dispensationalists mean by "spiritualizing Scripture," here is an example of what I suspect it means:

Revelation 4:1-2 "After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter.
And immediately I was in the spirit: and, behold, a throne was set in heaven, and one sat on the throne."

The Dispensational Bible teacher quotes this Scripture, and writes, "John is being taken up into heaven. Inasmuch as John was the last remaining apostle and a member of the Universal Church, his elevation to heaven is a picture of the Rapture of the Church just before the Tribulation begins." (Tim LaHaye, page 99, Revelation Unveiled.)

But who says that this is a picture of the rapture of the Church? Only the futurist scholar.
John was called, and immediately he, and he alone, found himself in the spirit in heaven. The Bible says nothing about the Church being raptured at that time. In fact, dispensationalists repeatedly harp on the fact that the Church is not mentioned any more until much later in Revelation. But if John's elevation into heaven was a picture of the rapture of the Church, it would seem odd if no one mentioned the Church at least once during all the visions that John saw. Could it be that this has nothing to do with any rapture of the Church?

This, in my opinion, is a clear-cut case of man spiritualizing Scripture, but the ones doing the spiritualizing are the dispensationalists, themselves.

cpmac
www.tribulationhoax.com