Or when he touches human uncleanness – any such uncleanness whereby one becomes unclean – and, though he has known it, the fact has escaped him, but later he realizes his guilt; Leviticus 5:3
Known – Leviticus describes proper worship. Its rituals and regulations govern the procedures for maintaining purity before the Lord in order to enter into worship. Many of the processes required in Leviticus concern accidental violations of ritual purity, and the steps needed to remove the impurity that results from those unintentional infractions. Most readers in Christian circles not only find these rituals confusing, they don’t even know why they are necessary. That’s because the Christian idea of proper worship has replaced Hebraic requirements with requirements invented by the Church. In general, the Church no longer acknowledges the Levitical need for ritual purity. It has substituted its own version of purity rituals, calling them biblical.
Buried in this text is a small, but familiar, Hebrew word that reveals our real dilemma. That word is yada’. This Hebrew verb covers the wide range of knowing, perceiving, learning, discerning, experiencing, considering and confessing. But the key to all this is that yada’ is about “ultimate knowledge, not initial knowledge.” Yada’ does not describe those things we suspect are true or imagine might be true. Yada’ is about what we know to be certain. In Hebrew thought, yada’ describes knowing the essence and purpose of something, that is, knowing it as it moves in the world. In this regard, yada’ is not about collected “facts.” It is about seeing into the ordered reality represented by the essential fit of something into the grand movement of life under God. When I say, “I know you,” I do not mean “I have your name on my computerized address book” or, “I recognize your picture from Facebook.” When I say, “I know you,” in Hebrew, I mean that I see into your purpose in the movement of life. I see how you fit into the fabric of God’s ordered existence. I see the essence of your being here.
When a man becomes ritually unclean, even though he knows in hindsight that he should have recognized the fit of his act into God’s ordered existence, but for some reason he did not comprehend the essence of that action as it occurred, then he is guilty. The perspective of this verse is not the perspective of the man as the act occurs. It is the perspective of the man after he knows for certain. In that moment, he realizes that he did know (in the ultimate and final sense) that his act was impure because its purpose didn’t change simply as a result of the passage of time. Its purpose was always a violation of ritual purity. Now he knows, and now he is accountable.
Sha’ul used the same Hebraic understanding in his comments about seeing in a glass dimly. Now we guess. Now we suspect. Now we act on the basis of so-far-as-we-know information. But the day is coming when it will be clear and we will discover what we have only dimly perceived is known in its ultimate form.
Does that mean all is hazy and uncertain? Of course not. Some things are now as certain as they will every be. Why? Because some things have been revealed to us by the One who already ultimately knows. Those things we can trust completely, not because we know them with certainty but because we know completely the One who reveals them.
Yada’ depends on batah (trust) and batah means to act with confidence on the character of the revealer. Now you know how you know.
Topical Index: know, yada’, Leviticus 5:3
 Baruch Levine, The JPS Torah Commentary: Leviticus, p. 32