(They swear by Allah that they said nothing (wrong)…) [9:74].
Said al-Dahhak: “The hypocrites set off with the Messenger of Allah for Tabuk. But whenever they met alone with each other, they insulted the Messenger of Allah, Allah bless him and give him peace, and his Companions and discredited the religion. Then Hudhayfah reported what they said to the Messenger of Allah, Allah bless him and give him peace. The Messenger of Allah, Allah bless him and give him peace, said to them: 'O hypocrites, what is this that I hear you have said?' They swore to him that they said nothing wrong, and so Allah, exalted is He, revealed this to give them the lie”.
Said Qatadah: “It was mentioned to us that a man from Juhaynah had a fight with another man from Ghifar and the latter had the upper hand. When he saw this, 'Abd Allah ibn Ubayy cried: 'O Banu Aws, help your brother for, by Allah, the like of us and the like of Muhammad is as it was said: fatten your dog and he will eat you. By Allah, once we enter Medina, the mighty among us will drive out the lowly'. A Muslim man heard this and informed the Messenger of Allah, Allah bless him and give him peace. When he sent for 'Abd Allah ibn Ubayy, the latter swore by Allah that he did not say it. Allah, exalted is He, revealed this to give him the lie”.
(And they purposed that which they could not attain…) [9:74].
Al-Dahhak said: “They were planning to push the Prophet, Allah bless him and give him peace, off his mount on the night of the steep road. These were men who agreed to kill the Messenger of Allah, Allah bless him and give him peace, while they were with him. They waited for an opportunity to take him by surprise. Their chance came when the Prophet, Allah bless him and give him peace, was taking a steep road. Some of them came forward while others stayed behind. It was night time. They said to each other: 'Once he starts going down this steep road, we will push him off his mount into the ravine'. His guide that night was 'Ammar ibn Yasir and his navigator was Hudhayfah. When Hudhayfah heard the sound of camels' hoofs, he looked behind and saw veiled men. He shouted: 'Go away, go away, O enemies of Allah!' They stopped and the Prophet, Allah bless him and give him peace, proceeded to his destination. Allah, exalted is He, then revealed (And they purposed that which they could not attain…)”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou