The Rishonim in masekhet Shevu'ot propose various explanations of the position that someone who lends to his fellow before witnesses must be repaid before witnesses.
The Baraita asserts that after a document is authenticated, other witnesses are not believed to say that the witnesses signed on the document were disqualified from giving testimony.
The Baraita asserts that if a second set of witnesses comes to disqualify the witnesses signed on a deed that had been properly authenticated, they are not believed.
