Ezra 9:2

For they have taken their daughters for themselves and for their sons, so that the holy seed has been mixed with the peoples of the lands; and in fact the captains and rulers have been the first to do this evil.

Exodus 22:31

You are to be holy men to me: the flesh of no animal whose death has been caused by the beasts of the field may be used for your food; it is to be given to the dogs.

Exodus 34:16

Or take their daughters for your sons; for when their daughters give worship before their gods, they will make your sons take part with them.

Ezra 10:18-44

And among the sons of the priests who were married to strange women were these: of the sons of Jeshua, the son of Jozadak and his brothers, Maaseiah and Eliezer and Jarib and Gedaliah.

Nehemiah 13:23-24

And in those days I saw the Jews who were married to women of Ashdod and Ammon and Moab:

2 Corinthians 6:14

Do not keep company with those who have not faith: for what is there in common between righteousness and evil, or between light and dark?

Deuteronomy 7:6

For you are a holy people to the Lord your God: marked out by the Lord your God to be his special people out of all the nations on the face of the earth.

Deuteronomy 14:2

For you are a holy people to the Lord your God, and the Lord has taken you to be his special people out of all the nations on the face of the earth.

Ezra 10:2

And Shecaniah, the son of Jehiel, one of the sons of Elam, answering, said to Ezra, We have done evil against our God, and have taken as our wives strange women of the peoples of the land: but still there is hope for Israel in this question.

Genesis 6:2

The sons of God saw that the daughters of men were fair; and they took wives for themselves from those who were pleasing to them.

Exodus 19:6

And you will be a kingdom of priests to me, and a holy nation. These are the words which you are to say to the children of Israel.

Deuteronomy 7:1-4

When the Lord your God takes you into the land where you are going, which is to be your heritage, and has sent out the nations before you, the Hittites and the Girgashites and the Amorites and the Canaanites and the Perizzites and the Hivites and the Jebusites, seven nations greater and stronger than you;

Nehemiah 13:3-4

So after hearing the law, they took out of Israel all the mixed people.

Nehemiah 13:17

Then I made protests to the chiefs of Judah, and said to them, What is this evil which you are doing, not keeping the Sabbath day holy?

Nehemiah 13:28

And one of the sons of Joiada, the son of Eliashib, the chief priest, was son-in-law to Sanballat the Horonite: so I sent him away from me.

Isaiah 6:13

And even if there is still a tenth part in it, it will again be burned, like a tree of the woods whose broken end is still in the earth after the tree has been cut down (the holy seed is the broken end).

Malachi 2:11

Judah has been acting falsely, and a disgusting thing has been done in Jerusalem; for Judah has made unclean the holy place of the Lord which is dear to him, and has taken as his wife the daughter of a strange god.

Malachi 2:15

... So give thought to your spirit, and let no one be false to the wife of his early years.

1 Corinthians 7:14

For the husband who has not faith is made holy through his Christian wife, and the wife who is not a Christian is made holy through the brother: if not, your children would be unholy, but now are they holy.

Treasury of Scripture Knowledge

Summary

For they have taken of their daughters for themselves, and for their sons: so that the holy seed have mingled themselves with the people of those lands: yea, the hand of the princes and rulers hath been chief in this trespass.

Bible References

Taken of their

Ezra 10:18
And among the sons of the priests who were married to strange women were these: of the sons of Jeshua, the son of Jozadak and his brothers, Maaseiah and Eliezer and Jarib and Gedaliah.
Exodus 34:16
Or take their daughters for your sons; for when their daughters give worship before their gods, they will make your sons take part with them.
Deuteronomy 7:1
When the Lord your God takes you into the land where you are going, which is to be your heritage, and has sent out the nations before you, the Hittites and the Girgashites and the Amorites and the Canaanites and the Perizzites and the Hivites and the Jebusites, seven nations greater and stronger than you;
Nehemiah 13:23
And in those days I saw the Jews who were married to women of Ashdod and Ammon and Moab:
Malachi 2:11
Judah has been acting falsely, and a disgusting thing has been done in Jerusalem; for Judah has made unclean the holy place of the Lord which is dear to him, and has taken as his wife the daughter of a strange god.

The holy seed

Exodus 19:6
And you will be a kingdom of priests to me, and a holy nation. These are the words which you are to say to the children of Israel.
Exodus 22:31
You are to be holy men to me: the flesh of no animal whose death has been caused by the beasts of the field may be used for your food; it is to be given to the dogs.
Deuteronomy 7:6
For you are a holy people to the Lord your God: marked out by the Lord your God to be his special people out of all the nations on the face of the earth.
Deuteronomy 14:2
For you are a holy people to the Lord your God, and the Lord has taken you to be his special people out of all the nations on the face of the earth.
Isaiah 6:13
And even if there is still a tenth part in it, it will again be burned, like a tree of the woods whose broken end is still in the earth after the tree has been cut down (the holy seed is the broken end).
Malachi 2:15
... So give thought to your spirit, and let no one be false to the wife of his early years.
1 Corinthians 7:14
For the husband who has not faith is made holy through his Christian wife, and the wife who is not a Christian is made holy through the brother: if not, your children would be unholy, but now are they holy.

Mingled

Genesis 6:2
The sons of God saw that the daughters of men were fair; and they took wives for themselves from those who were pleasing to them.
Nehemiah 13:3
So after hearing the law, they took out of Israel all the mixed people.
2 Corinthians 6:14
Do not keep company with those who have not faith: for what is there in common between righteousness and evil, or between light and dark?

The hand

Ezra 10:18
And among the sons of the priests who were married to strange women were these: of the sons of Jeshua, the son of Jozadak and his brothers, Maaseiah and Eliezer and Jarib and Gedaliah.
Nehemiah 13:4
Now before this, Eliashib the priest, who had been placed over the rooms of the house of our God, being a friend of Tobiah,

General references

Exodus 34:16
Or take their daughters for your sons; for when their daughters give worship before their gods, they will make your sons take part with them.
Deuteronomy 7:3
Do not take wives or husbands from among them; do not give your daughters to their sons, or take their daughters for your sons.
Nehemiah 10:30
And that we would not give our daughters to the peoples of the lands, or take their daughters for our sons;

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain