When the Holy Prophet (S) proclaimed the religion of Islam in Medina, Abdullah bin Ubayy became extremely jealous; so he resorted to a conspiracy, dug a pit in his house and erected poison coated knives and lances and covered it all by a thick mat or carpet.
He also tied a border of that carpet with a wall so that when the Holy Prophet (S) and his companions arrive, they may fall in that pit. He also hid some of his evil-minded companions armed with swords, so that when the Holy Prophet (S), Ali (a.s.) and other companions come out, they might be attacked and killed. Besides, he also prepared poisoned food so that if the first plan fails, they may be finished by the poisoned food.
Finally he went and invited the Holy Prophet (S) and his close companions for the feast, and the Almighty Allah, through angel Jibraeel, informed the Holy Prophet (S) about all these evil plans. Jibraeel (a.s.) advised the Prophet to sit where the mischief-maker Abdullah bin Ubayy might suggest and also to eat the food offered by him so that this miracle may be observed by them all quite clearly.
In short, the Holy Prophet (S) went to that fellow’s house with his companions and sat on the carpet prepared by him. Yet they remained safe because Allah had hardened the carpet and the ground beneath it became stony and leveled. The hypocrites were amazed beyond measure. Then he put the poisoned food before his guests. Before extending his holy hand to the food, the Holy Prophet (S) asked Ali to recite these words (as he himself recited): In the Name of Allah, the Beneficent, the Merciful. In the Name of Allah, the Healer. In the Name of Allah, the Sufficient. In the Name of Allah, the Protector. In the Name of one, after taking Whose Name nothing and no pain can harm, neither on earth nor in the sky and He is the Hearer, the Knower.
Then all of them ate the food, got satisfied and returned hale and hearty. When companions of Abdullah bin Ubayy saw this, they thought that perhaps he had forgotten to poison the remaining food, so they poisoned it. His daughter who had prepared all these plans saw that the mouth of that pit had been closed and that it had become hard like the ground she herself sat on.
But when she sat, Almighty Allah reverted that to its earlier condition and that cursed woman fell down into it and died and the inmates of that house began to weep and cry in grief. Abdullah bin Ubayy warned the people of his house and ordered them not to say that she died after falling in the pit otherwise, they will be disgraced and Muhammad will know that it was all due to their conspiracy.
So they were weeping and saying: The bride for whose marriage this feast was arranged, has died. And all who ate that leftover food also died. When Abdullah bin Ubayy came to the Prophet, the latter asked the cause of that girl’s death. The great liar replied that the girl fell down fatally from the upper floor of the house and all who ate, died due to overeating. Thus the conspirators did not reveal the true cause.