Proverbs 2:17

who forsakes the companion of her youth and forgets the covenant of her God;

Jeremiah 3:4

Have you not just now called to me, 'My father, you are the friend of my youth--

Proverbs 5:18

Let your fountain be blessed, and rejoice in the wife of your youth,

Ezekiel 16:8

"When I passed by you again and saw you, behold, you were at the age for love, and I spread the corner of my garment over you and covered your nakedness; I made my vow to you and entered into a covenant with you, declares the Lord GOD, and you became mine.

Ezekiel 16:59-60

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

Malachi 2:14-16

But you say, "Why does he not?" Because the LORD was witness between you and the wife of your youth, to whom you have been faithless, though she is your companion and your wife by 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 in the wife of your youth,
Jeremiah 3:4
Have you not just now called to me, 'My father, you are the friend of my youth--

Forgetteth

Ezekiel 16:8
"When I passed by you again and saw you, behold, you were at the age for love, and I spread the corner of my garment over you and covered your nakedness; I made my vow to you and entered into a covenant with you, declares the Lord GOD, and you became mine.
Malachi 2:14
But you say, "Why does he not?" Because the LORD was witness between you and the wife of your youth, to whom you have been faithless, though she is your companion and your wife by covenant.

General references

Exodus 20:14
"You shall not commit adultery.
Leviticus 15:20
And everything on which she lies during her menstrual impurity shall be unclean. Everything also on which she sits shall be unclean.
Numbers 5:12
"Speak to the people of Israel, If any man's wife goes astray and breaks faith with him,

The Holy Bible, English Standard Version® copyright © 2001 by Crossway Bibles, a publishing ministry of Good News Publishers.