Mark 10:8

And the man and his wife shall become one;' so that they are no longer two, but one.

1 Corinthians 6:16

Or do not you know that a man who unites himself with a prostitute is one with her in body (for 'the two,' it is said, 'will become one');

Ephesians 5:28

That is how husbands ought to love their wives--as if they were their own bodies. A man who loves his wife is really loving himself;

Treasury of Scripture Knowledge

Summary

And they twain shall be one flesh: so then they are no more twain, but one flesh.

General references

Bible References

One flesh

1 Corinthians 6:16
Or do not you know that a man who unites himself with a prostitute is one with her in body (for 'the two,' it is said, 'will become one');
Ephesians 5:28
That is how husbands ought to love their wives--as if they were their own bodies. A man who loves his wife is really loving himself;

General references

Ephesians 5:31
'For this cause a man shall leave his father and mother, and be united to his wife; and the man and his wife shall become one.'