Translation of the verse 32 from Surah Al-Anfal : Number of verses 75 - - page 180 - Part 9.
And (remember) when they said: "O Allah! If this (the Quran) is indeed the truth (revealed) from You, then rain down stones on us from the sky or bring on us a painful torment."
And [remember] when they said, "O Allah, if this should be the truth from You, then rain down upon us stones from the sky or bring us a painful punishment."
(8:32) And also recall when they said: 'O Allah! If this indeed be the truth from You, then rain down stones upon us from heaven, or bring upon us a painful chastisement.' *26
*26). These words were uttered by way of challenge rather than a prayer to God. What they meant was that had the message of the Prophet (peace be on him) been true, and from God, its rejection would have entailed a heavy scourge, and stones would have fallen on them from heaven. Since nothing of the sort happened, it was evident that the message was neither true nor from God.