There are different themes explored in the book of Ezekiel. It opens with a vision of the priest where he is visited by god. It ten goes on to the prophecy of the destruction of Jerusalem. This is explained as god’s punishment. Finally, the book closes with promises of hope and salivation.
The basic theme is that sinner are warned again and again and their refusal to commit to God lead to his anger that resulted in God sending a physical warning by exiling Israelites. However, this punishment was given as means of showing the sinners that he existed and to be humble and ask for penance. Finally he shows that god is merciful with his promises of salivation and hope.