[Those] who said, 'Indeed, Allah has taken our covenant not to believe any messenger until he brings to us an offering which fire [from heaven] will consume.' Say, 'There have already come to you messengers before me with clear proofs and [even] with that which you speak of,' regarding the offering that fire consumes; yet you did not believe them and killed them. 'So why did you kill them, if you should be truthful?' that Allah had taken such a covenant with you. He means by this their ancestors. Spoils of war before this nation [were not permissible for them]; they used to collect them, then fire would descend from the sky upon them and consume them.

Mujahid said: When a man would give charity and it was accepted from him, fire would descend upon it.