What they heard him say in the middle of a prayer
They saw him reach out for something that was not there.
أَعُوذُ بِاللَّهِ مِنْكَ
Aʿūdhu bi-Llāhi mink
“I seek refuge in Allah from you.”
Where this comes from
Abu ad-Darda says he stood to pray and they heard him say it, then curse three times, and stretch out his hand as though taking hold of something. Afterwards they asked. He said the enemy of Allah had come with a torch of fire to throw in his face, and that had he not remembered a prayer of Sulayman he would have tied him to a pillar of the mosque for the children of Madinah to play with.
The full narration
Abu Darda' reported:Allah's Messenger (ﷺ) stood up (to pray) and we heard him say:" I seek refuge in Allah from thee." Then said:" curse thee with Allah's curse" three times, then he stretched out his hand as though he was taking hold of something. When he finished the prayer, we said: Messenger of Allah, we heard you say something during the prayer which we have not heard you say before, and we saw you stretch out your hand. He replied: Allah's enemy Iblis came with a flame of fire to put it in my face, so I said three times:" I Seek refuge in Allah from thee." Then I said three times:" I curse thee with Allah's full curse." But he did not retreat (on any one of these) three occasions. Thereafter I meant to seize him. I swear by Allah that had it not been for the supplication of my brother Sulaiman he would have been bound, and made an object of sport for the children of Medina
Source
Ṣaḥīḥ Muslim · 1211
- Agreed upon as authentic (al-Bukhārī / Muslim)