[18:93] When he reached the valley between two palisades, he found people whose language was barely understandable.
[18:94] They said, "O Zul-Qarnain, Gog and Magog are corruptors of the earth. Can we pay you to create a barrier between us and them?"
[18:95] He said, "My Lord has given me great bounties. If you cooperate with me, I will build a dam between you and them.
[18:96] "Bring to me masses of iron." Once he filled the gap between the two palisades, he said, "Blow." Once it was red hot, he said, "Help me pour tar on top of it."
[18:97] Thus, they could not climb it, nor could they bore holes in it.
[18:98] He said, "This is mercy from my Lord. When the prophecy of my Lord comes to pass, He will cause the dam to crumble. The prophecy of my Lord is truth."
[18:99] At that time, we will let them invade with one another, then the horn will be blown, and we will summon them all together. One of my duties as God's Messenger of the Covenant is to state that Gog and Magog, the final sign before the end of the world, will reappear in 2270 AD (1700 AH), just 10 years before the end. Note that Gog and Magog occur in Suras 18 and 21, precisely 17 verses before the end of each sura, representing 17 lunar centuries (see 72:27 and Appendix 25).

[21:95] It is forbidden for any community we had annihilated to return.
[21:96] Not until Gog and Magog reappear, will they then return - they will come from every direction.
[21:97] That is when the inevitable prophecy will come to pass, and the disbelievers will stare in horror: "Woe to us; we have been oblivious. Indeed, we have been wicked." By the year 2270 AD, thanks to God's mathematical miracle in the Quran (Appendix 1), America will be the heart of Islam, and billions around the globe will have believed in the Quran (9:33, 41:53, 48:28, 61:9). Gog and Magog (allegorical names of villainous communities), will be the only bastions of heathenism, and they will attack the submitters. That is when the world will end (15:87, 18:94, Appendix 25). Gog and Magog are mentioned in 18:94 & 21:96, 17 verses before the end of each sura; this may indicate the time of their appearance.