Rambam, Hilchos Eidus, Chapter 14: 

Chapter 14: scenarios in which an invalid witness becomes valid

Halacha 1: The status of a spouse invalidation after the death of the wife

· A man who was invalid for testimony on one’s behalf due to being a husband of one’s relative, becomes revalidated after his wife, who is one’s relative, passes away.

· This applies even if the couple had children together.

Halacha 2: The status of one who witnessed the testimony prior to his invalidation

· By relatives: A person who witnessed a certain matter which requires testimony prior to becoming one’s relative, and then became one’s relative such as one’s son-in-law, is nonetheless invalid.

· However, after this witnesses wife passes away and he is no longer his son-in-law, then he is reinstated to his validity to testify.

·  By disabilities: Likewise, if a person was mentally sane at the time that he witnessed the testimony, and then became a deaf-mute or became insane, was able to see and then became blind, nevertheless he is invalid. If, however, he returns to a state of sanity, and sight, then his validity to testify is reinstated.

· The rule is as follows: So long as one witnessed the testimony while valid, and is now testifying while valid, then it his testimony is acceptable even though he went through a state of invalidation in the interim. However, if the witnessing of the testimony or the actual testimony is in a time of invalidation, then the testimony is invalid.

· Testifying on testimony that one witnessed as a child: From the above it’s understood that one cannot testify as an adult regarding something he witnessed as a child.

Halacha 3: Cases in which it is valid to testify regarding matters that one witnessed as a child.

· By rabbinical related matters, it is valid for an adult to testify regarding something that he witnessed as a child. The following are a list of cases in which such testimony is acceptable:

1) Signatures: One can testify regarding his father’s, or teachers, or brothers’ signature which he witnessed as a child, being that the validation of a document is only rabbinical required.

2) Kesuba and Besula: One can testify regarding a woman that she was a virgin when she got married, based on that as a child he saw her wedding take place as is customary for virgins. The reason for this is because majority of women are virgins when they get married, and the Kesuba is only rabbinical required.

3) Beis Haperas cemetery: One can testify to knowledge that he attained while still a child regarding an area having the status of a Beis Haperas cemetery.

4) Techum Shabbos: One can testify regarding the distance of Techum Shabbos that as a child he witnessed being followed.

5) Kohen: One can testify that as a child he saw a certain individual act as a Kohen, in order to allow them to eat rabbinical Teruma.

6) Lineage: One can testify as to the lineage of an individual who is a Kohen, and as to whether he is a valid Kohen or an invalid Kohen, as he heard it from his father when he was a child.

Halacha 4: A convert testifying on testimony he witnessed prior to conversion

· A convert testifying on testimony he witnessed prior to conversion has the same laws as an adult testifying on testimony he witnessed as a child, both for validation and invalidation.

Halacha 5: Validating the signature of a witness who became invalid

· Became a Rasha: If a valid witness signed a document and then became invalid either due to transgression of a sin, such as stealing, or due to becoming a relative of the person, such as his son-in-law, that they not only can he no longer testify to his signature, but even another two witnesses cannot can testify to it, and hence the only way to validate the document is if the court can establish the signature from previously signed documents, which were signed prior to his transgression.

· Becoming a relative: If a valid witness signed a document and then became invalid either due to transgression of a sin, such as stealing, or due to becoming a relative of the person, such as his son-in-law, that although he can no longer testify to his signature, another two witnesses can testify to it, and hence validate the document.

Halacha 6: The status of the document that was signed by invalid witnesses but witnessed by valid witnesses

· If two witnesses sign on a document and one of the witnesses is invalid due to being a Rasha, then the document is invalid even if two valid witnesses witnessed the handing over of the document to the other party.

· The same applies if both signatories were relatives of each other.

Halacha 7: Relative invalidation of witnesses who signed on a document with many recipients

· If the witnesses which signed on the document are a relative of one of the parties, then they become invalid for both parties, if the matter is considered a single testimony.

· For example, if they signed that an individual agreed to give half of one’s assets to two different people, and these signatories are a relative of one of the recipients, then the document is invalid for both recipients.

· If, however, there are two testimonies written on the document, then even if the signatories are found to be a relative of one of these parties of transactions, they remain valid for the other parties of transactions.

· For example, if the document states that an individual agreed to give one present to one individual and another present to another individual, and it is found that the signatories are relatives of one of the recipients, then the other recipient still maintains a valid document.