Whoever Was Served Meat and He Did Not Know Whether the Name of Allah Was Mentioned Over it or Not

Question :

What should we do if we are served meat to eat and we do not know whether the Name of Allah was mentioned over it or not?

Answer:

It has been confirmed in Sahih Al-Bukhari, on the authority of 'A'ishah, may Allah be pleased with her, that some people said: "O Messenger of Allah! Some people come to us with meat and we do not know if the Name of Allah was mentioned over it or not." The Messenger of Allah said:
"You mention His Name and then eat it."

She said: "And they had recently abandoned disbelief."

Such people might be ignorant of the subsidiary and exact rulings, which are not known except to those who live among the Muslims. For this reason, the Prophet advised those who asked to concentrate their attention on their own action, saying: "You mention His Name and then eat it." That is, you mention His Name over the food and then eat it.

As for the slaughter of one other than yourselves, whose action is correct, it (i.e. his slaughter) is considered valid and you should not ask about it, because this is a form of stubbornness and obstinacy.

If we were to say that it is necessary to ask about things such as this, we would exhaust ourselves, due to the possibility that every food served to us is not permissible. So if someone invites you to eat and serves food to you, it is possible that the food is unlawful or stolen, and it is possible that the money paid for it was unlawful, and it is possible that the meat therein did not have the Name of Allah mentioned over it, and so on.

It is from Allah's Mercy towards His creatures that if an action was performed by one who has experience therein, then what is apparent is that it was done in a manner which meets one's obligations and no sin is attached to a person thereby.

Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 6 Pages 286-287