A call to moral sanity will always involve a call to rejoice in marriage. In studying to comment on this passage I noticed an interesting dichotomy among commentators. Many shied away from speaking of sexual love in marriage when referring to things in this passage. They wanted to make all the allusions and word pictures within it refer to children instead. I found this a little sad, because between this passage and the entire book of Song of Solomon, God does not even remotely shy away from the subject of the joys of physical intimacy within marriage. In the past too many in the church felt to speak of such things was dirty or out of bounds. But in donig so we relegated the idea of physical pleasure in sex to those who engaged in it outside the bounds of marriage. Now I am not advocating that we go into explicit detail about such things, because God has informed us in Hebrews that we are to keep the marriage bed holy, but I am saying that where God's Word addresses such things, we should not be afraid to address them as well.
What we are encouraged to do here in this passage is to rejoice in the wife of our youth. We are told that to enjoy physical intimacy with our wife is to allow our fountain to be blessed. The fountain here is a picture of a life-giving source - and the blessed result of sexual intimacy within marriage is that children are produced - which continues the cycle of life. But God is not just speaking of having a child - He is speaking of the process of intimacy which is enjoyed within the sexual union of a married couple. He says that this should be a time when we are blessed. That means God, who made us sexual beings - and who also designed our sexual organs - knew that this was going to be an enjoyable act. He commands us here, through the father speaking to His son, that we should rejoice in the wife of our youth. It is clear that what is said in the following verses refers to love-making between a husband and wife. God wants that to be enjoyable.
Please remember though the context of this passage. This is a father instructing his son about the dangers of sexual immorality and warning him to stay away from adultery and from fornication. It is wonderful to see that in the midst of a talk on moral sanity that a father would tell his son that God's intent for sex is that it be thoroughly enjoyed within the framework of biblical marriage. This is sexual sanity - and it is ignored only to the detriment and hurt of those who do so. But for those who grasp God's view of sex - who see it as God intended for it to be enjoyed - this talk between father and son is wonderfully liberating. It lets us know that God did create sex - and He created the biological reality that sex is very pleasurable. But it tells us such things within the context of God's intent for sexual union. And that can ONLY be blessed within the bonds of marriage. Within that union there is no guilt, no STD's, no prospect of illegitimacy, and no sense of sin. But when we get outside the boundaries which God has set for sexual intimacy, such things abound. That is why it is so vital that we speak with our sons and daughters of such things - because to leave those topics to others is only to surrender them to the sexual insanity that now rules the greater part of mankind.