Gog from Magog

Gog of Magog is mentioned in Eze 38:1–39:20. Gog of Magog will be the leader of a great army that attacks the land of Israel. Magog may be Russia, as it's said to be the furthest north (Eze 38:6, 15, 39:2), but we can't be sure. Other nations will also follow Gog (Eze 38:5): Persia (Iran), Cush (Sudan) (see the video 
The Black Pharaohs: The Kingdoms of Kush), Put (Libya, North Africa),
Gomer, and Togamah (Turkey). 

The Lord will force Gog to start the war even if it's done reluctantly by Gog
(Eze 38:4a, 39:2). Gog will be motivated by his own evil plans (Eze 38:10) but the attack will be in line with God's will. One reason for Gog's attack may be to capture natural resources or large possessions from Israel (Eze 38:12–13).

The attack will happen at "the latter years" (Eze 38:8a), that is, at the end times.
The attack comes when Israel is at peace with its neighbors (Eze 38:8b, 11, 14).
Israel may have peace when Israel's covenant with surrounding nations is signed at the beginning of Daniel's 70th week (also known as the 7-year Tribulation period
(Dan 9:27a)), see Visions and Dreams by Prophet Daniel. This war will likely begin close before Israel's covenant with surrounding nations is signed, see 
What is Babylon in the Book of Revelation?

In a supernatural way, the Lord  takes hold and rains fire and brimstone on Gog's soldiers and on the many people who follow him (Eze 38:22, 39:6). Gog will be defeated by God himself on the mountains of Israel (Eze 39:4). The slaughter will be so great it will take seven months to bury all the dead (Eze 39:11–12).

For seven years, Israel will be able to use Gog's weapons and war materials as fuel and energy sources (Eze 39:9). The Tribulation period is for seven years and then
Jesus returns, and it's most likely that the use of Gog's weapons and war materials won't extend past the time of the Tribulation period. 

The Gog war isn't the same as the Antichrist's war against Israel at the end of the Tribulation period (Zechariah 14:2). Gog isn't the same person as the End Time Antichrist, see Who is the End Time Antichrist? The reasons are as follows:

• The Gog war consists of an alliance of states while the Antichrist attack comes from all the nations of the world.
• When the Gog war takes place, Israel is said to dwell in safety and prosperity (Eze 38:8b, 11, 14). It hardly seems possible at the end of the Great Tribulation period when Antichrist murders all who don't want to take the mark of the beast and catastrophic judgments fall from heaven, see The Horses in the Book of Revelation.
• Gog's motive is strategy and wealth while Antichrist's motive is a "holy/spiritual" war.
• Gog is buried in Israel (Hes 39:11) while Antichrist is thrown alive into the Lake of Fire, see Lake of Fire in What Does the Bible Say about Hell?
• Gog reluctantly goes against Israel. Antichrist attacks fully for the extermination of Israel and the Jews.

Gog and Magog are also mentioned in Rev 20:7–9, but that passage doesn't refer to the same people and events mentioned in The Book of Ezekiel. The names Gog and Magog in The Book of Revelation are used to figuratively describe God's enemies. It's used to show that these people will show the same rebellion against God as those in The Book of Ezekiel, but it's not the same war.

Reasons why Eze 38:1–39:20 and the war at the end of the millennial kingdom
(Rev 20:7–9) refer to different people and battles are as follows:

• In the battle of Eze 38:1–39:20, the armies come mainly from the north and involve only a few nations on Earth (Eze 38:2–6, 15, 39:2). The battle of Rev 20:7–9 will involve all nations, meaning armies will come from all directions, not just from the north.
• There is no mention of Satan in the context of Eze 38–39. In Rev 20:7 the context clearly places the battle at the end of the millennial kingdom with Satan as the protagonist.
• Eze 39:11–12  states that the dead will be buried for seven months (Eze 39:12). Since Rev 20:8–9 is immediately followed by the Great White Throne judgement (Rev 20:11–15), it can’t be the same event.

Eze 39:21–29 talks about what will happen when Jesus returns.

See also The Book of Ezekiel.

Ezekiel's Temple

Will Ezekiel's temple (also called the Third Temple), described in Eze 40–48,
be built, and animal sacrifices as well as the Levitical priesthood be re-established?
If so, will it be before Jesus returns or during the millennial kingdom
(the thousand years kingdom of Christ)? Is it biblical?

The Temple Institute is making preparations for a third temple to be built. Its
long-term goals are to build a third Jewish temple on the Temple Mount, on the site occupied by the Dome of the Rock, and to reinstate the worship of animal sacrificial. 

When Jesus died on the cross, he took away all our sins (for those who believe in him, see Salvation), and after that there is no need for animal sacrifices. This was symbolically signified by the rending of the veil in the temple when Jesus died on the cross (Mat 27:51, Mark 15:38, Luke 23:45), see The Rending of the Veil of the Temple. Christ's body was sacrificed once and for all (Heb 10:8–10). The purpose of the offerings in Ezekiel's temple is to ”make atonement for the house of Israel” 
(Eze 45:17). See also Eze 43:20, 26, 45:15, 20 that all say it's about atonement.
The sacrifices are presented as an atonement for sin, not as a memorial. Jesus recommends the use of wine and bread to commemorate his death 
(1 Cor 11:23–26, Luk 22:19–20). God wouldn't replace this with animal sacrifice,
as he never found much pleasure in it (Psalm 40:7, 51:18–19, Heb 10:6).

This disqualifies a building of Ezekiel's temple after Jesus' death on the cross, 

as it would say that Jesus' death wasn't enough. To take elements from the
Mosaic Laws in the New Covenant would be to introduce a different gospel than the one preached by Apostle Paul, see The Book of Galatians. The Book of Hebrews was addressed to Jews who had accepted the gospel and become Christians, and who were subject to persecution and public pressure to bring in elements from the 
Mosaic Laws into the New Cabinet to ease public pressure on them.
Its author explains how the Old Testament points to Jesus and that we now live
in a New Covenant that has replaced the Old Covenant (Heb 9:12–14, 10:4).

Ezekiel was given a detailed vision about this temple in Eze 40–48, about 573 BC
(Eze 40:1–4), during the Babylonian captivity. That means it can’t be
Solomon's Temple which was destroyed in 587 BC by Nebuchadnezzar when he conquered Jerusalem, see The Book of Habakkuk.

It can't be the Second Temple built when the Jews returned from Babylon about 538 BC and completed around 516 BC. That temple was rebuilt to be Herod’s Temple (still seen as the Second Temple), see the short video Herod's Temple - Interesting Facts. It was destroyed by the Romans in 70 AD. This temple was much smaller and less elaborate than the temple that Ezekiel describes.

Ezekiel would bring this vision of the temple to the house of Israel,
to make them repent (Eze 43:10–11). 

Antichrist will in the end time sit in God's temple and proclaim himself as God
(2 Thess 2:3–4). He will also abolish the daily sacrifices (Dan 8:11–12, 9:27), see Who is the End Time Antichrist? It means that the temple is built at the end time and that the animal sacrifices are reinstituted. But that temple can't be a true fulfillment of Ezekiel's temple described in Eze 40–48, because God's true temple is now the body of Christ. The believers of Christ are the body of Christ,
that is, the temple of God (1 Cor 3:16–17, 6:19, 2 Cor 6:16, Eph 2:19–22), see 
Jesus the Light of the World. Jesus predicted that the glory of God would leave the physical temple (Mat 23:37-38), which happened when he gave his life for us on the cross. God doesn't dwell in houses made by human hands (Acts 7:48–50, 17:24). The only way that Antichrist can destroy God's true temple is to persecute believers on a massive scale (Mat 24:21–22). Their bodies are living sacrifices (1 Pet 2:5, 
Rom 12:1). By persecuting the believers, the daily sacrifices are abolished.
See living sacrifice explained at time 33:56–34:47 in Hebrews 12 (Part 4) :18-29.
But even so, Antichrist will abolish the daily sacrifices in the physical temple
when he sits in it and proclaims himself as God.

The interpretation of Eze 40–48 is therefore a conditional outline of what might have been if the house of Israel had repented to obedience to the Lord, which didn't occur. 

It can’t be built during the millennial kingdom, because it involves a complete abrogation of Jesus' final sacrifice on the cross, in addition to the denial of the eternal Priesthood after the order of Melchizedek (Heb 7:11–28), see Melchizedek in The Book of Hebrews. The Tribe of Dan is mentioned in Eze 48:1–2. But this tribe was probably assimilated long before the millennial kingdom, see the end part of Man-Made Religion and The 144,000 in the Book of Revelation.

A physical third temple will be built before Jesus returns, but will be a false temple, it won't be Ezekiel's temple. It won't be a dwelling house for God. This false temple can even be called the temple of God (2 Thess 2:4, Rev 11:1). Such a temple will likely be dedicated in God's name, but he won't be present there. There are Bible verses that indicate that such a false physical temple will exist during the Tribulation period (Mat 24:15–16, Dan 8:11, 9:27 (LXX), 11:31, 2 Thess 2:3–4, Rev 11:2), see Interpretations of the 70th Week in the Book of Daniel in 
When Did Jesus Die and when Was He Born? See also:

• Time 28:08–28:58 in Bible Q & A With Pastor Paul │ July 2023. 
• Time 14:14–20:04 in Revelation 10 and 11 • "No more delay".

Such a temple temple can be built on the Temple Mount near the Al-Aqsa Mosque, see time 11:38–14:40 in Third Temple Crucial To Understanding Hamas/Israel War.

Animal sacrifices in this temple won't be holy but blasphemous. Only Jesus' substitutionary death on the cross takes away sin. This would be the state of this physical temple in the middle of the seven-year Tribulation period, before it's desecrated by Antichrist, who claims to be God (2 Thess 2:3–4, Mat 24:15, 26b, Mark 13:14, Dan 8:11, 9:27 (LXX), 11:31). If done at Passover (in April), and since Jesus returns 3.5 years after (Dan 12:11–12), he would then return in October, see End of Time in When Did Jesus Die and when Was He Born?

Dan 9:27 says (see also Which Version of the Old Testament did Jesus Use?):

• ESV: "And he shall make a strong covenant with many for one week,
  and for half of the week he shall put an end to sacrifice and offering.
  And on the wing of abominations shall come one who makes desolate, until the decreed end is poured out on the desolator."
• LXX: "And one week shall establish the covenant with many: and in the midst of the week my sacrifice and drink-offering shall be taken away:
  and on the temple [shall be] the abomination of desolation;
  and at the end of time an end shall be put to the desolation."

See also the "abomination of desolation" explained at the times 32:15–42:15, 47:05–52:42 in Matthew 24:1-20 – The Temple and the Key Prophetic Sign, and 9:00–24:38 in Matthew 24:21-51 – The Great Tribulation and the End of the Age.

See also The Book of Ezekiel.