In this segment, the Chofetz Chaim examines a case in which you are wrongly accused of something, and it is obvious that the real wrongdoer had to be either you or someone else within your circle.
Obviously, it would be forbidden to inform on the real culprit. The Chofetz Chaim tells us that the halachah does allow you to say, “I didn’t do it.” However, in cases where there are only two possible culprits and saying “I didn’t do it” automatically places the blame on the other person, other factors need to be considered in deciding the halachah (see Be’er Mayim Chaim §43).
Even where you are allowed to say, “I didn’t do it,” this response would be considered acting according to the strict letter of the law. However, it is considered praiseworthy to go beyond the letter of the law and actually accept the blame to protect the guilty party.
Obviously, the Chofetz Chaim is recommending this only for someone with the emotional strength to absorb the consequences. He is certainly not recommending that one do something which would cause him great distress or involve him in a feud. On the other hand, there are situations in which there is much to be gained by accepting the blame for someone else.
For example, suppose someone feels slighted because he was not invited to an important shul (synagogue) function which you helped organize. If you have an established, close relationship with the person, he is more likely to be forgiving of your wrongdoing than he would be toward someone else. If you accept the blame for this oversight, your friend will understand that no harm was intended, and the tension will be defused.