That is why a man leaves his father and mother and is united to his wife, and they become one flesh.
I have always thought of this strictly in terms of marriage, and this verse is certainly a clear and obvious reference to that. But I wonder – could it not also be tied to the “be fruitful and multiply” verses that come later?
When a husband and wife are ‘united’, the end result of that can often come in the form of ‘one flesh’ – i.e. in the form of a baby. That is the ultimate culmination of a husband and wife being ‘united’, isn’t it?
Of course, there are those couples who, because they are unfortunate victims of this broken world, are unable to experience the wonder of making ‘one flesh’. However, that does not change the truth of the statement: A man and a woman are to marry, and as husband and wife, to procreate. This both guarantees the future of the human race, and strengthens the bond between them.
Even Paul, who was never married himself, understood the importance of intimacy between a husband and wife:
Do not deprive each other except perhaps by mutual consent and for a time, so that you may devote yourselves to prayer. Then come together again so that Satan will not tempt you because of your lack of self-control. – 1 Cor 7:5
Here Paul is saying intimacy is not just important for your marriage relationship, but that it actually helps keep Satan at bay! How easy it must be for him to tempt those who do not enjoy the God-given gift of intimacy with their spouse. And we can help to frustrate the devil's efforts if we keep our marriage strong and intimate. Frustrate the devil? Count me in!
That is a good enough reason, of course, but then the even greater blessing comes if, through our intimacy, we are blessed with a newly created life! As a father myself, I understand that there is nothing that draws a husband and wife together in God quite the same way that a child can.
So to all you married couples – go forth, be fruitful and multiply. The fruit that results just might become “the apple of your eye” later!