Gog/Magog War (the reasons for the attack)
Why will they attack?
Why these nations will attack Israel is answered in two parts by the text. The first answer is seen in verses 10-13:
Ezekiel 38:10-13 (NIV)10 “‘This is what the Sovereign LORD says: On that day thoughts will come into your mind and you will devise an evil scheme. 11 You will say, “I will invade a land of unwalled villages; I will attack a peaceful and unsuspecting people–all of them living without walls and without gates and bars. 12 I will plunder and loot and turn my hand against the resettled ruins and the people gathered from the nations, rich in livestock and goods, living at the center of the land.” 13 Sheba and Dedan and the merchants of Tarshish and all her villages will say to you, “Have you come to plunder? Have you gathered your hordes to loot, to carry off silver and gold, to take away livestock and goods and to seize much plunder?”‘
Verses10-12 tell us that the incentive for the attack is the spoils of war, or, “plunder & loot.”
I will plunder and loot and turn my hand against the resettled ruins
“Have you gathered your hordes to loot, to carry off silver and gold, to take away livestock and goods and to seize much plunder?”
Noted specifically are silver, gold, livestock, goods and general plunder. Understanding Ezekiel’s world view, each of these most likely imply his known generalization of the spoils of war for his day. In short, the motive will be greed. Israel will have something which the attackers desire to have for their own.
One possible source of desired plunder has been suggested to be the Dead Sea. The Dead Sea is the second largest salt lake on Earth, and contains sodium, chlorine, sulfur, potassium, calcium, magnesium & numerous other minerals and chemicals which could be harvested. Its salt content is over 8 times that of the ocean and among many other anomalies it produces asphalt deposits. Any number of potential future chemical or mineral needs could cause the Dead Sea to become a commodity of great interest.
Other potential plunder could be energy, as Israel is a global leader in areas of geothermal energy, diamonds, or Israel’s general wealth, being exceptional throughout the Middle East. Whatever the attacking nations may state as their purpose when this attack comes, the Bible states their real purpose is greed for some element of plunder.
Ezekiel 38:13 indicates that there are nations which will speak against the coalition of nations for this attack, but in word only.
Sheba and Dedan and the merchants of Tarshish and all her villages will say to you, “Have you come to plunder? Have you gathered your hordes to loot, to carry off silver and gold, to take away livestock and goods and to seize much plunder?”
Sheba and Dan are the areas of modern day northern Arabia, while Tarshish and all her villages is a bit more difficult to discern. “All her villages” probably indicates other nations spawned from Tarshish, but determining exactly which geographical area is indicated by the name “Tarshish” is a bit puzzling.
There are several historical regions which have been named Tarshish. Of those which have spawned other nations, one is as the city of Tartessos in Southern Spain, or a Tarshish of England.
If the Tarshish of Spain is that referenced by Ezekiel, then “her villages” would be South and Central America, with the exception of Brazil. If England is the Tarshish referenced by Ezekiel, “her villages” would include the USA, Canada, Australia, New Zealand & some other western democracies.
Who precisely opposes this attack is not too highly relevant, however, since their opposition is that of word only, and nothing is done to defend Israel in the attack. What is perhaps the most important deduction from this part of the text is that Sheba, Dan and Tarshish at least understand the true motives of the attack to be that of greed and are not fooled by any other potential excuse.
The second answer to the question of “why will they attack” is answered from God’s perspective. Clearly the coalition who is attacking has their own motives, but Ezekiel 38 informs us that God himself has a motive for this attack; for it is he who allows it to take place, and even more so, it is he who instigates this coalition to embark on this attack.
Ezekiel 38:14-16 (NIV)14 “Therefore, son of man, prophesy and say to Gog: ‘This is what the Sovereign LORD says: In that day, when my people Israel are living in safety, will you not take notice of it? 15 You will come from your place in the far north, you and many nations with you, all of them riding on horses, a great horde, a mighty army. 16 You will advance against my people Israel like a cloud that covers the land. In days to come, O Gog, I will bring you against my land, so that the nations may know me when I show myself holy through you before their eyes.
Verse 16 says” I will bring you against my land, so that the nations may know me when I show myself holy through you before their eyes.” From God’s perfect perspective, this purposes of this attack are to reveal his glory. Specifically, his glory is to be revealed to “the nations.” When this battle is complete, God will have revealed himself in a very powerful way. In fact, it will be resolved with God’s direct intervention so that no one will be capable of failing to realize that it is God himself who has redeemed Israel from her attackers hands.
It may seem troubling to some that God himself would inspire nations to do that which would be considered wrong and ungodly. However, this will certainly not be the first time God has done such a thing. Romans 9:17 states “For the Scripture says to Pharaoh: “I raised you up for this very purpose, that I might display my power in you and that my name might be proclaimed in all the earth.” God chose for Pharaoh, an ungodly king, to rise to power and do ungodly things so that God could demonstrate his power through Pharaoh to the world. A similar condition exists in the Gog-Magog war. God will instigate this coalition of nations to come against his chosen people so that he can demonstrate his power to the nations of Earth.
The context of Ezekiel 38 indicates that this attack will happen in close historical proximity to the beginning of the Great Tribulation. In chapter 37 God speaks of a coming time when he will do a work which will bring Israel back together as one nation under one king; the Messiah, David’s heir. Then, in chapter 40, following this text, a description of the Millennial Temple is given, which sandwiches this story between the time God begins his work of redeeming Israel and the time when that redemption is complete, under Messianic rule. Thus, this invasion must be close in proximity to the period of the Great Tribulation, but it cannot be during the Great tribulation for reasons which will be seen later in the text.
It seems, then, that this invasion is a catalyst for the world to begin paying attention to Israel and her estranged God, whom will bring her back into his fellowship, at this point, just a few short years in the future. Being a pre-tribulational event itself, perhaps this invasion is another sign likened to the signs of Matthew 24, which will quicken mankind to begin watching the stage of world events for the coming of God’s judgments on the whole of the Earth.
It will also soon be observed that God’s program for the Great Tribulation is in part to draw men to repentance. The comprehension of God’s glory will certainly play a role in that draw.
 Goetz, P.W. (ed.) The New Encyclopaedia Britannica (15th ed.). Vol. 3, p. 937. Chicago, 1986