Genesis chapter 4 starts with this:
Now Adam knew Eve his wife, and she conceived and bore Cain, saying, "I have gotten a man with the help of the LORD." (Gen 4:1)Now, no one thinks, "Look at that! It took 4 chapters for Adam to finally meet his wife!" No, we know -- we all know -- what is meant by "knowing" his wife. Even the world will refer to "know in a biblical sense" as a euphemism for sex.
But think about that for a moment. You see, for a euphemism to make sense, there has to be some connection to the thing to which it alludes. I mean, you couldn't use, say, "Adam yellowed his wife" and have it be meaningful in any way. Or take a classic biblical example. When Jesus and His disciples heard that Lazarus had died, Jesus said, "Our friend Lazarus has fallen asleep, but I go to awaken him." (John 11:11) Now, His disciples misunderstood. "Oh, good! He's sleeping. He'll get better." "No," Jesus had to tell them, "he's dead." "Sleep", then, was a euphemism for "dead". And that works because "sleep" has characteristics in common with "dead". You know, eyes closed, not doing anything, "dead to the world", that kind of thing. There is a parallel that makes it work. And it really worked in the Lazarus story because, after all, Jesus was going to "wake him up", so to speak.
So what about Adam knowing his wife? That, too, is a less ... direct way of saying that the two had sexual relations. But in order for it to be useful, it has to have some connection with the real thing. How does "know" correlate to "have sex with"? The term, as a stand-in for the sexual relationship, is full of meaning.
When today's world thinks of sex, we often think of recreation, pleasure, fulfillment, eroticism, lots of that kind of stuff. This biblical version is knowing. It is an intimacy, an interpersonal relationship. It is deeper than "acquainted" and it is relational, not merely physical. Today we have terms for sex that illustrate how surface it has become. From "bumping uglies" to "doing the nasty", we've clearly moved off of "knowing".
The word used here, yâda‛, also has another component in most of its uses in Scripture. We read, for instance, God speaking to the king of Judah,
"Do you become a king because you are competing in cedar? Did not your father eat and drink And do justice and righteousness? Then it was well with him. "He pled the cause of the afflicted and needy; Then it was well. Is not that what it means to know Me?" declares the LORD. (Jer 22:15-16)Or how about this?
A righteous man has regard for the life of his animal, But even the compassion of the wicked is cruel. (Prov 12:10)In both of these cases the "knowing" was not about a sexual relationship, but did have a purpose. That purpose was to be intimate enough with the one known as to give them what was needed. In the first case, it was knowing God well enough to do what He wanted. In the other it was to know livestock well enough to supply their needs. This, too, is in view with Adam knowing his wife. The loving husband will supply his wife with the intimacy she needs, including and especially in the bedroom.
There is another interesting aspect to the word. Later in Genesis we read,
For I know him, that he will command his children and his household after him, and they shall keep the way of the LORD, to do justice and judgment; that the LORD may bring upon Abraham that which he hath spoken of him." (Gen 18:19)That was the King James. It was God speaking to Himself about Abraham. And He said He knew him. But modern translations don't translate it "know". They translate it "have chosen". Because there is, in this word, a special relationship. A covenant relationship. It is seen in Matthew when Jesus tells the false prophets, "And then will I declare to them, 'I never knew you; depart from Me, you workers of lawlessness.'" (Matt 7:23) You see, it wasn't that He had no knowledge of them. It was that He had no special relationship with them. And that, too, is embodied in the biblical "to know".
Our modern version of sex is almost completely physical. In our rush to make it more "available", we've stripped it of all of its nuance and meaning. The biblical version includes intimacy -- knowing. It includes an awareness of the needs of the other as well as an intention of meeting those needs. It includes a relationship, a covenant connection. The biblical picture of the sexual act is not a physical singularity. It is a union, a sharing, a unique relational process of intimacy, deeper than body to body, but soul to soul. Today's version, far more popular, is also far inferior.