The ruling on vouching for witnesses before the judge

Question:
Some people, especially in the courts, are asked to vouch for their witnesses, so they bring people who do not know the witnesses, but they vouch for them, and sometimes the judge does not ask them about it. What is the ruling on this?

Answer:
This is not permissible. It is not permissible for anyone to vouch for a witness unless he knows that the witness is just and truthful. As for if he does not know him, it is not permissible for him to vouch for him. Allah the Exalted said: If you do not know him, you say, "By Allah, I do not know him," or you know that he is not truthful and not upright, yet you praise him with what he does not possess and vouch for him. This is more dangerous: that you deny the defects in him and vouch for him, while you know that he is not worthy of vouching. No, this is more severe.
The bottom line is that a person does not vouch for anyone before the judge unless he knows him completely, because this matter is a responsibility on him, and the judge will rely on it, and Allah the Exalted will question him about it on the Day of Resurrection.