ציטירנדיקער פּירוש אויף יהושע 7:19

In fact, if one speaks of money which is under dispute it is impossible to be a witness unless one has seen and has knowledge of what has been agreed upon. However, it is possible to understand the verse in such a way that it does speak of three separate situations. Each of the situations would be a testimony all by itself. There is such a thing as having witnessed something with one’s eyes without one understanding the meaning of what one has seen. Similarly, it is possible to have knowledge of something even if one has not seen it with one’s eyes. There can even be testimony involving neither seeing nor having knowledge. Let me illustrate: If someone observed Reuven handing over money to Shimon but he did not know whether this money was a loan, a repayment of a loan, or a deposit for safe-keeping, or even if the recipient was a messenger taking possession of the money on behalf of the person who had asked him to do so; in all these cases merely seeing something is not sufficient basis for relevant testimony. The reverse, i.e. knowledge of something without having witnessed the truth of the statement with one’s eyes could be that Reuven heard Shimon admit that he had borrowed money from him. Since at the time he admitted it he did not make repayment, Reuven is in no position to testify to a transaction. The testimony of such a witness may still be of benefit to the plaintiff even when there is neither knowledge of a transaction or the transaction having been witnessed in cases where the person called upon to testify knows the signature of the party or parties concerned and can affirm or deny them. His testimony may help the plaintiff recover his money on the basis of the debtor’s signature to a document being independently confirmed. You could therefore justify the meaning of the word או as meaning “or” in the words והוא עד או ראה או ידע “and he is (either) a witness, or saw, or knew, etc.”
On the words: אם לוא יגיד ונשא עונו, “if he fails to testify he shall bear his iniquity,” our sages (Sifra Vayikra 11,5) comment that the meaning is that he fails to testify in a place where he is duty-bound to testify, i.e. at court. If such a witness withholds his testimony in private conversation with either of the litigant parties he is not guilty of anything. The Torah’s warning applies to him only if he fails to testify in a legitimate court. A Biblical example is Achan who was not obligated to reveal his misdemeanor before Joshua took him to court. This is why Joshua pleaded with him: (Joshua 7,19) “please tell me what you have done (i.e. confess).” Seeing that there have to be at least 2 litigants, one witness, and three members of the court, the letter ו in the word והגד, in that verse was added to allude to the 6 people involved. In our verse too the word לוא instead of being spelled לא as is customary, had the letter ו added in order to make the same point. It suggests that “if not,” the party concerned will be guilty of the penalty implied in the words ונשא עונו, “he will bear his guilt.” The allusion is that he is guilty only if he fails to testify in the presence of the 6 people represented by that letter ו.

תן לו תודה – and even though a person is not killed by his own [admission], the killing of Achan (Joshua 7:19-20) was a special dispensation (i.e., a decision under an emergency).

When he is about ten cubits away from the place of stoning, they say to him, ‘confess’, for such is the practice of all who are executed, that they [first] confess, for he who confesses has a portion in the world to come. For so we find in the case of Achan, that Joshua said to him, “My son, pay honor to the Lord, the God of Israel, and make confession to him. [Tell me what you have done, do not hold anything back from me.” And Achan answered Joshua and said, “It is true, I have sinned against the Lord the God of Israel, and this is what I have done” (Josh. 7:19-20). And how do we know that his confessions made atonement for him? As it says, “And Joshua said, “What calamity have you brought upon us! The Lord will bring calamity upon you this day” (Josh. 7:35), [meaning] this day you are a calamity, but you are not to be a calamity in the next world. And if he does not know how to confess, they say to him, “Say, may my death be an expiation for all my sins.” When the convict reaches ten cubits distance from the place where he is to be stoned, he is asked to confess of his crimes. The mishnah teaches that anyone who confesses, no matter how heinous their crime, has a place in the world to come. This lesson is based the story of Achan in the book of Joshua. When Joshua conquered Jericho, the people were not supposed to take anything from the city. Rather they were supposed to kill anything that was alive and bring only the silver and gold to the treasury. Achan violated this ruling and took from the proscribed property of Jericho. As a punishment God causes Israel to lose their subsequent battle at Ai (Joshua, chapter 7). When Joshua figures out that their loss was due to Achan’s taking from the proscribed property, he sentences Achan to death for having violated God’s word not to take from the property of Jericho. Joshua requests of Achan to confess his crime, which he subsequently does. The innovation that our mishnah makes is that this confession expiates Achan of his crime and Achan therefore has a place in the world to come. Joshua says to Achan, “What calamity have you brought upon us! The Lord will bring calamity upon you this day”. The simple sense of the verse is that God is punishing Achan and carrying out the punishment today. The midrashic reading of our mishnah is that God is punishing Achan only today, and he will not punish him tomorrow. Achan, therefore, has a place in the world to come. Even one who does not know how to confess is taught how to do so. The Rabbis are concerned that although the criminal’s time in this world is drawing to a close, he should still be able to have a share in the world to come.