{N}1,{/}1: To understand the book of Ezra, it might be helpful to read the Introduction.
We note that only those who accept "being liberated" will be sent home. There can be no liberation or external help for the indifferent. 
Those who return {C}are those whose spirit  has been aroused by God{/}.

{N}3,{/}1: For the Jews, the restoration of the Temple became an opportunity to rediscover how different they were from all the other nations in that they served the only God. It also allowed them to affirm their identity as Jews among the people of the country, since working together strengthens unity.
We will also note that, when they first arrived from exile, they generously offered to provide all that was needed to build the Temple (2:68). Yet, twenty years go by and the intervention of the prophets Haggai and Zechariah was needed to implement the projects agreed upon in the enthusiasm of their return.

{N}4,{/}1: With the support of the prophet Haggai (see Hg 2:10) the Jews refuse Samaritan cooperation in rebuilding the Temple. They have no desire to mix anything unclean in this religious endeavor. To put it differently, they are determined to build a community based on the practice of the Law and cannot accept that unconverted people have any claim on the Temple.
The same thing happens now as well. Though we might wish to welcome everyone, we cannot surrender holy things nor leadership of the communities to unconverted people. Neither can the Church accept political support which would compromise its freedom.
The story begun in 4:1-5 continues in chapters 5 and 6. The Jews remain steadfast, and Providence helps them. They are assisted by Tattenai, the Persian governor of the province West-of-Euphrates, including all of Palestine with Samaria as the capital.

{N}4,{/}6: The letter found in 4:6-23 corresponds to a later intervention on the part of the Samaritan notables when, a few years later, the Jews try to build the Jerusalem walls.

{N}7,{/}1: Almost sixty years passed between what is related in chapter 6, the Passover of 515 and Ezra's mission. Ezra may have come in 458 or he may also have come in 427 after Nehemiah's first mission. Then, these chapters 7-10 should be read after Chapter 6 of Nehemiah.
Ezra was in the Persian province of Babylon as the person in charge of Jewish religious affairs. He was a priest and belonged to the groups which had meditated on the Law of Moses under the influence of Ezekiel. They had gathered the different texts and may even have edited the biblical books forming "the Law" - from Genesis to Deuteronomy - into their final version. These priests understood that Israel was beginning a new phase of its history. The Jews who had returned from the Exile must be guided by God's Law. This law, which separates Jews from non-Jews and regulates all the details of life will become the foundation of a religious community - and later also of a political community - making them a united people.
Upon coming to Jerusalem with an official mission, Ezra intends to impose the Mosaic Law edited in its final form; the Jewish people are reborn as the people of the Law.
The Law will transform the Jewish people into a more faithful and responsible people, serving God in every detail. This also entails the risk of confusing authentic faith with external practices. A people who equate serving God with Temple worship and religious practice only can become indifferent to what is most important in life.

{N}7,{/}21: Note this section where the strict master of the Law, Ezra, appears very human and likable.

{N}9,{/}1: The Jews were intermingled with people who did not share their religion and thus they were in danger of losing their identity. Ezra is worrying about the future and thinks that the identity of Jewish people now living among not-Jewish must be strengthened by very strict laws. The prohibition of marrying with not Jewish persons is one of the key elements of this legislation: God's people will never be confused with the others, even leaving in the same territory and family will necessarily be Jewish.
The barriers built by Ezra proved very effective and we may see the will of God there. The Jewish people resisted very harsh persecutions (see Maccabees). Then, after the coming of Christ, they were dispersed and had to live for almost twenty centuries among officially Christian countries that usually persecuted them or tried to convert them to the Christian faith through every means. Possible yet, the Jewish people have remained unique in history - in part, thanks to their faithfulness to the Law. Christians can also draw a lesson from all of this. If we are called to be yeast for the masses, co-existing without prejudices with people of different creeds, we also need demands and external practices, accepted by all who join our Christian community.
See what is said to this effect in Nehemiah 13.

