Proverbs 2:17

Who forsakes the companion of her youth, and forgets the covenant of her God.

Jeremiah 3:4

Will you not from this time cry unto me, My father, you are the guide of my youth?

Proverbs 5:18

Let your fountain be blessed: and rejoice with the wife of your youth.

Ezekiel 16:8

Now when I passed by you, and looked upon you, behold, your time was the time of love; and I spread my skirt over you, and covered your nakedness: yea, I swore unto you, and entered into a covenant with you, says the Lord GOD, and you became mine.

Ezekiel 16:59-60

For thus says the Lord GOD; I will even deal with you as you have done, who have despised the oath in breaking the covenant.

Malachi 2:14-16

Yet you say, Why? Because the LORD has been witness between you and the wife of your youth, against whom you have dealt treacherously: yet is she your companion, and the wife of your covenant.

Treasury of Scripture Knowledge

Summary

Which forsaketh the guide of her youth, and forgetteth the covenant of her God.

Bible References

The guide

Proverbs 5:18
Let your fountain be blessed: and rejoice with the wife of your youth.
Jeremiah 3:4
Will you not from this time cry unto me, My father, you are the guide of my youth?

Forgetteth

Ezekiel 16:8
Now when I passed by you, and looked upon you, behold, your time was the time of love; and I spread my skirt over you, and covered your nakedness: yea, I swore unto you, and entered into a covenant with you, says the Lord GOD, and you became mine.
Malachi 2:14
Yet you say, Why? Because the LORD has been witness between you and the wife of your youth, against whom you have dealt treacherously: yet is she your companion, and the wife of your covenant.

General references

Exodus 20:14
You shall not commit adultery.
Leviticus 15:20
And everything that she lies upon in her impurity shall be unclean: everything also that she sits upon shall be unclean.
Numbers 5:12
Speak unto the children of Israel, and say unto them, If any man's wife go aside, and commit a trespass against him,