The Book of Ezekiel

Ezekiel was a contemporary with Jeremiah, see the Prophet Jeremiah, and Daniel, see Visions and Dreams by Prophet Daniel. Ezekiel and Daniel were prophets for the Jews during the Babylonian captivity. Jeremiah was a prophet for the Jews, mostly while they were still in their homeland, in Judah.

Ezekiel got a vision that he was at God's Throne in Heaven. There he was called by God to be a prophet to the Jews (Eze 2:1–5, 3:4–6). They wouldn't listen to him, because they had a hard forehead and a stubborn heart (Eze 3:7). God told him not to be afraid of them and what they said, and not to be dismayed at their appearance, for they were a rebellious people (Eze 2:6–7, 3:8–9).

God had made Ezekiel a watchman for the Jews. Whenever he heard a word from God, he had to warn the people. If God tells the wicked to die, and Ezekiel doesn't warn him to turn from his way, he will die in his iniquity, but God will make Ezekiel responsible for his death. If Ezekiel warns the wicked to turn from his way, and he doesn't, that person will die in his iniquity, but Ezekiel has saved his soul.
(Eze 33:1–9).

It was a very dangerous thing to be a prophet among the Jews. You may be mistreated and even lose your life. The Jews only wanted to hear what pleased them, see itching ears.

God's word is sweet as honey (Eze 3:1–3, Psalm 119:103, Proverbs 24:13).
It can be bitter in the stomach when it's about something I don't want to hear,
when it's about judgement (Rev 10:9–10).

God gave the following message through Ezekiel:

• The one who sins is the one who will die. The child won't share the parent's guilt, nor will the parent share the child's guilt. The righteousness of the righteous will be credited to them, and the wickedness of the wicked will be charged against them. (Eze 18:4–20).
• If a wicked person turns away from all the sins he has committed and keeps all God's decrees and does what is just and right, that person will surely live, he won't die (Eze 18:21–23, 27–28, 33:14–16, 19).
• If a righteous person turns from his righteousness and commits sin and does the same detestable things that the wicked do, he will die
  (Eze 18:24, 26, 33:12–13, 18).

God has no pleasure in the death of the wicked, but that the wicked turns from his way and live (Eze 33:11).

Ezekiel prophesies about the fall of Jerusalem. God would execute judgments on the city because the Jews had rebelled against God's rules and statutes by doing evil more than the nations around them. They worshipped pagan idols. (Eze 5:5–17, 8:3–18). God would bring his wrath upon Jerusalem. The righteous people who lived there couldn't rescue the city. But God would let a remnant of the people be taken
to Babylon (Eze 14:12–23). These deportations were done in several stages, see
The Book of Habakkuk. God would cut off both the righteous and the wicked from Jerusalem (Eze 21:3–4). The wicked would lose their lives, but the righteous would be part of the remnant taken to Babylon. The people who were still in Jerusalem believed that they were blessed and those who had been deported to Babylon
weren't. But it was the other way around. (Eze 11:13–16).

There were leaders among the Jews who devised iniquities and who gave evil counsel in Jerusalem. They said that the people didn't need to worry about the Babylonians. (Eze 11:1–3). God told Ezekiel to prophesy against them (Eze 11:4–12). 
These leaders didn't care about the people (Eze 34:1–10).

God told him to prophesy against the prophets who saw false visions and gave lying divinations, who prophesied about Jerusalem and saw visions of peace for her,
when there was no peace. (Eze 13:1–23, 22:25, 28). 
See also Prophecy in Spiritual Gifts. 

Their priests gave false teachings (Eze 22:26). Their princes were like wolves 
(Eze 22:27). The people practiced extortion and committed robbery. They oppressed the poor and needy and mistreated the foreigner and denied them justice 
(Eze 22:29).

God told Ezekiel to symbolize what king Zedekiah, the last king of Judah 
(see Zedekiah of Judah in Kings of Judah and Israel), would try to do when
he later tried to escape from Jerusalem (Eze 12:1–15). When he did, he was captured (2 Kings 25:1–7, Jer 52:4–11, 39:6–10, Isaiah 22:2–3). Five years later (587 BC), Jerusalem was destroyed (Eze 12:21–28). God also told through Ezekiel
The Parable of Two Eagles and a Vine. 

God was true to his word and brought the Babylonian army that destroyed Jerusalem along with the temple in 587 BC (Eze 33:21), see The Book of Habakkuk.

God would bring the descendants to the deported people back to their homeland (Eze 11:17–21), see Prophet Jeremiah. 

Ezekiel uses the picture of the ruler of Tyre to describe Satan (Eze 28:11–19),
see also Explanation to Satan's Attack on the Woman in the Book of Revelation:

He was the signet of perfection, full of wisdom and perfect in beauty (Eze 28:12).

He was in the Garden of Eden (Eze 28:13).

He was an anointed guardian cherub (Eze 28:14a), see God's Throne in Heaven.

He was on God's holy mountain (Eze 28:14b).

He was blameless in his ways from the day he was created, until iniquity was found in him (Eze 28:15). 

God threw him from the mountain of God, because he was filled with violence and sinned because of his misuse of contacts with other angelic beings (Eze 28:16). 

His heart became proud because of his beauty, and he corrupted his wisdom for his splendor (Eze 28:17). He wanted to be like God (Isaiah 14:13–14).

He is a murderer and the author of lies (John 8:44).

He will come to a dreadful end and will be no more forever (Eze 28:19). 
He will be cast into the Lake of Fire (Rev 20:10), see
The Millennial Kingdom and the Great White Throne Judgement.

Ezekiel had a vision of a new temple, see Ezekiel's Temple.

He received a vision of Israel's end times, see The Valley of Dry Bones.

Ezekiel prophesied an attack on Israel near to the beginning of the
seven-years Tribulation period, see Gog from Magog.

He also speaks of the second coming of Messiah (Eze 16:60–63, 
34:11–12, 16b–22, 27b, 36:11b, 25–29a, 31–32, 38b, 39:21–22, 28–29),
see Messiah's Second Coming in in The Prophecies of Isaiah.

He speaks of the millennial kingdom (Eze 20:40–44, 28:25–26). Jesus will then
rule the world from Jerusalem. God will put David as leader over Israel
(Eze 34:23–24, 37:24–25, Hos 3:5). God will protect Israel, and the land will prosper (Eze 34:13–16a, 25–27a, 28–31, 36:8–11a, 24, 29b-30, 33–38a,
39:23–27). See also The Millennial Kingdom in The Prophecies of Isaiah.

See also The Prophet Books in the Old Testament.