The obedience of the church at Philadelphia comes up at the beginning of Revelation 3:10. It says, “Because you have kept my command to persevere, I also will keep you from the hour of testing that is going to come upon the whole world to test those who dwell on the earth” (3:10). Perseverance is one of the works that is pleasing to Christ in the seven letters and in the book of Revelation. It is something that is necessary for the people of Christ who live in the midst of a world that tests their faithfulness to Christ. Jesus promises that he will keep his obedient people “from the hour of testing” that will come “upon the whole world” in the form of God’s plagues of judgment (3:10). Revelation portrays the protection of the people of God from God’s wrath in Revelation 7:3 and 9:4. Before God’s plagues do any harm, angels place a seal upon the servants of God to mark them for protection from God’s plagues. Jesus is speaking about the eschatological plagues of God in Revelation 3:10 and not about persecution of Christians by the Devil, the Beast, and the people of the Beast. These plagues will test only “those who dwell upon the earth,” which is the way that Revelation speaks about the people of the Dragon and the Beast, not the people of God (3:10). Therefore, the “hour of testing” is not something that the church of Philadelphia or any Christian should fear (3:10). The believers at Philadelphia are being tested by the “synagogue of Satan” (3:9), but the future will bring a time of intense testing that will test the persecutors of God’s people.
This paragraph is slightly edited portion of my book:
Paul Hoskins, The Book of Revelation: A Theological and Exegetical Commentary, pp. 109-10 (that page provides further sources and footnotes that I have omitted above).