Mark 10:8

and the two will become one flesh.’ So they are no longer two, but one flesh.

Note Genesis 2:24 (see also LXX)

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

and the two will become one flesh, so that they are no longer two, but one flesh.

and the two shall become one flesh: so that they are no more two, but one flesh.