In the book of Revelation, Christ said,
“Since you have kept my command to endure patiently, I will also keep (tereo) you from (ek) the hour of trial that is going to come upon the whole world to test those who live on the earth.” Revelation 3:10
Most students agree that “the hour of trial that is coming on the whole world” most likely refers to the Great Tribulation.
Greek dictionaries translate “tereo” as follows:
Tereo, tay-reh'-o; to guard (from loss or injury, prop. by keeping the eye upon, to keep unmarred): -hold fast, keep (-er), (ob-, pre-, re) serve, watch.
Tereo means to attend to carefully, take care of, to guard, to keep one in that state in which he is.
The Greek word ek is very common and it is used over 800 times in the NT. It is translated 25 different ways including: among, at, because of, by, from, of, on, out of and with.
The Greek words tereo and ek used together carries the meaning to be kept within the sphere of. If one wished to communicate the idea of removal they would use, “tereo” with apo which means to be kept outside of.
However, the best test is to allow Scripture to interpret Scripture. Since we already know these two words are used commonly in the New Testament, how can we accomplish this with any certainty?
In this case we are indeed fortunate. As it turns out there is only one other place in the entire Bible in which the two Greek words, "tereo ek” are used together. And the Apostle John is the person who uses "tereo ek” in both cases. Revelation 3:10 is the first case and this is the second.
John 17:15 My prayer is not that you take them out of the world but that you protect (tereo) them from (ek) the evil one.
Allowing Scripture interpret Scripture we see that the believers will be protected throughout the Great Tribulation not removed out of it.
We find proof of this when we see that God's people are protected during the Tribulation, as we read here.
And out of the smoke locusts came down upon the earth and were given power like that of scorpions of the earth. They were told not to harm the grass of the earth or any plant or tree, but only those people who did not have the seal of God on their foreheads (Revelation 9:3-4).
There is no biblical support for the Pre-Trib Theory!