Reading Revelation 12:17 in context, it shows that in the future, just prior to Christ's return, some in God's Church will be protected from the Great Tribulation and Satan's wrath, while other Christians will have to go through that terrible time of martyrdom.
Revelation 12:17 reads: "And the dragon [Satan the devil] was enraged with the woman [the Church of God], and he went to make war with the rest of her offspring, who keep the commandments of God and have the testimony of Jesus Christ."
We begin our discussion of this passage by quoting from chapter 13 of our free booklet, "Is That in the Bible?--The Mysteries of the Book of Revelation":
In Matthew 24, containing the famous "Olivet prophecy," Jesus Christ explained the "sign of His coming and the end of the age" (verse 3). After discussing the "beginning of sorrows" (verse 8), He pointed at the worldwide preaching of the gospel (verse 14), followed by the Great Tribulation (beginning with verse 15). In that context, Jesus said, in verses 19-22:
"You are the light of the world. A city that is set on a hill cannot be hidden."
-Matthew 5:14