Matthew 19:6 - Ellicott's Commentary On The Whole Bible

What therefore God hath joined. — Strictly interpreted, the words go further than those of Matthew 5:32, and appear to forbid divorce under all circumstances. They are, however, rather the expression of the principle that should underlie laws, than the formulated law itself, and, as such, they assert the true ideal of marriage without making provision (such as was made before) for that which violates and annuls the ideal. It is remarkable that the essence of the marriage is made to depend, not on laws, or contracts, or religious ceremonies, but on the natural fact of union. Strictly speaking, that constitutes, or should constitute, marriage. The sin of all illicit intercourse, whether in adultery, or concubinage, or prostitution, is that it separates that union from the relations and duties which the divine order has attached to and makes. if Simply minister to the lusts of man’s lower nature. The evil of every system that multiplies facilities for divorce is that it treats as temporary what was designed to be permanent, and reduces marriage, so far as it goes, to concubinage durante bene placito. This may, in some stages of social progress, as the next verses indicate, be the least of two evils; but it does not cease to be an evil, and the efforts of all teachers and legislators should be directed to raise the standard of duty rather than to acquiesce in its debasement.