Ezekiel 8

1 This vision occurred about a year after Ezekiel was called by God (Ezek 1:2) and six years after he was taken into exile. It seems likely that Ezekiel had called the exiled leaders of Judah together at the command of God for this revelation. The following vision revealed many of the idolatrous practices that were taking place in the Temple in Jerusalem. If Ezekiel had not been in these areas or known about these practices from other sources, it would be true evidence to them that God had directly revealed these secrets to him.
2 This description seems most like an angel. The next verse says that the Holy Spirit lifted Ezekiel up which either means that the being described is a theophany of the Spirit or that the Spirit lifted Ezekiel while the angel held him by the hair.
3 Ezekiel makes it clear that this is a vision, which means that his physical body did not move from his house as the elders watched.

The gate was probably a large sheltered door that housed a large idol. God was angry with this because in order for men to approach the altar and the temple they had to pass by this idol and would likely pay homage to it. Any idol worship is an affront to God, and having an idol in His designated Temple enraged Him.

4 God had chosen to place His Name at the Temple in Jerusalem. At this point God's glory still resided there, even though the people could not see it. He would soon depart because of their idolatrous practices and then allow their enemies to destroy the place.
10 This room might have been originally designed to hold the money offerings or other items related to worship in the Temple. It had been converted into a hall of idols. The Temple had been transformed from God's worship center to a worship center for the gods.
11 Ironically, Shaphan was the one who found the scroll of God that prompted king Josiah to return Judah to worshiping God (2 Ki 22:3-23:25). These examples were forgotten and Judah quickly turned back to the idols they loved to worship.

The next verse indicates that the people felt that God had left them. They turned to other gods attempting to appease any of them to the point of blessing Judah with protection. But this effort was in vain since carvings and statues can do nothing. Instead of alleviating the situation such activity would only make it worse since they were offending God who what the only one who could really protect them.

14 Tammuz was a god associated with spring. The myth said that he would die at the end of summer and then come back to life at springtime, thus explaining the seasons. Perhaps the Jews didn't see that the seasons cycled whether or not they worshiped this so-called god.
16 The temple had been designed specifically so that worshipers would face away from the rising sun and thus avoid worship of the heavenly body. But men found it very easy to turn around and face east while they offered sacrifices on the altar. The obvious symbolism is that people turn their backs on God when they choose to worship something else.
17 When the people turned away from God they also stopped following His commands. This resulted in injustice and violence. Perhaps the idiom here expresses the idea of children who put things in their noses without realizing the danger posed by them if they fall down.
18 God has boundless mercy, but He also knows when a person is hardened in sin to the point where they will never repent. At that point God may choose to destroy them so that they will not continue to be a bad influence on the surrounding people.