What is the ruling on the testimony of one who testifies to the debtor's acknowledgement of the debt, but did not witness the original contractual event?

It is permissible to testify based on what was heard regarding the property owner's acknowledgment of the amount, even if the payment itself was not witnessed. This is because testifying to what is known and heard is sometimes obligatory to save a Muslim's wealth, based on the Almighty's saying: "And do not conceal testimony, for whoever conceals it, his heart is indeed sinful." However, it is not permissible to testify that payment occurred unless it was witnessed, because one of the conditions for testimony is direct observation, and due to the Prophet's hadith (definition): "Do not testify except to a matter that is as clear to you as the brightness of this sun."