At the end of Christ's message to the church at Pergamum, He writes,
He who has an ear, let him hear what the Spirit says to the churches. To the one who conquers I will give some of the hidden manna, and I will give him a white stone, with a new name written on the stone that no one knows except the one who receives it.’ (Revelation 2:17)
In the refrain that we've heard in the letters to the previous churches, we are called to hear what the Holy Spirit says to these seven churches and, by extension, all the churches of God.
And we see another promise of the Savior given "to the one who conquers", i.e., to the one who endures to the end. Here, we see that the Savior will give the one who conquers "some of the hidden manna" (v. 17). There are various ideas about what this hidden manna is, but the main idea is that it is nourishment. In the Old Testament, when the Israelites were in the wilderness, God provided for them manna. It was an unknown substance, which is, in fact, why they called it "manna", which is derived from the Hebrew word "mān", which means "What is it?" It was a miraculous substance that God provided for them every day while they were in the wilderness.
So, for Christ to say that He would provide "some of the hidden manna" for the one who conquers, He's saying that He's going to take care of them. They're suffering now, but Christ is going to take care of them forever.
He'll also give them "a white stone" (v. 17). Again, there are various ideas about what this white stone was. White stones were used as attendance tickets to banquets, to declare guiltlessness in a courtroom, or even as signs of victory to athletes or warriors. Each of these has spiritual parallels in Christianity, so it's unclear what exactly is meant in this particular context. In any case, this white stone is a reward for conquering. If you endure to the end, Christ will give you a white stone.
And on this white stone, "a new name [will be] written on the stone that no one knows except the one who receives it" (v. 17). Again, there's some mystery on this. What would be the purpose of the new name? I don't know if anyone knows for sure, but it has often been tied to a personal and intimate relationship with God. This name would only be known by God and the person receiving the white stone.
So, while there's a lot unclear about this verse, this much is clear: Christ will reward the one who endures to the very end. It's an encouragement for us to keep running hard. Specifically, with the context of this letter to the church at Pergamum, we're encouraged to hold fast to Christ's name and not deny His faith, and not tolerate sin and falsehood in the church. The Spirit will give us all we need to be faithful to Christ, and in the end, our Savior and King will reward us. All glory be to Him!