Hodaas Baal Din

It is well known that a person cannot testify about himself l'zchus, for his benefit. However, a person may testify about himself to be mechayev himself. This is the concept of hodaas baal din kmeah eidim. The question is, how precisely does this idea work?

The Ktzos HaChoshen addresses this in a number of places (34:4, 37:1, 5, 9). First, we must address why a person cannot testify about himself l'zchus. The Ktzos brings two possibilities. First, maybe it is merely a chshash mesheker, we fear the person is lying. If so, it is understood why a person would be believed l'chov. The Ir Shushan has a different possibility. He holds that a person isn't believed l'zchus because of the psul of karov. We employ the rule of adam karov eitzel atzmo (a person is related to himself). If this is the case the question remains, why is a person allowed to testify on himself l'chov?

There are many possibilities offered. Some say the person is actually mechayev himself b'toras matanah. It's not that we really believe him that he owes the money. It's just that if he wants to give money to someone else, he is certainly entitled.

Along the same lines, some suggest there is a migo to believe him. After all, he could just give the money as a matanah if he wanted.

The Shach answers that a person isn't a karov to himself l'gabay chov.

Finally, the Ktzos himself learns the whole thing as part of the gezairas hakasuv by modeh b'miktzas, that even though a person is a karov to himself, the gezairas hakasuv overrides.