At-Tawbah: 74
"They swear by Allah that they did not say..."
The Messenger of Allah (ﷺ) stayed in the Tabuk expedition for two months, during which the Qur’an was revealed to him, criticizing the hypocrites who stayed behind. Those of them who were with him heard this, among them al-Julas ibn Suwayd.
Al-Julas said: "By Allah, if what Muhammad says is true regarding our brothers whom we left behind—who are our masters and nobles—then we are worse than donkeys."
‘Amir ibn Qays al-Ansari said to al-Julas: "Yes, by Allah, Muhammad is truthful, and you are worse than a donkey."
This reached the Messenger of Allah (ﷺ), so he summoned him. Al-Julas swore by Allah that he had not said it. ‘Amir raised his hand and said: "O Allah, reveal to Your servant and Prophet that which confirms the liar and verifies the truthful one."
Then, "They swear by Allah that they did not say [it]" was revealed.
Al-Julas said: "O Messenger of Allah, Allah has offered me repentance. By Allah, I did say it, and ‘Amir spoke the truth." So al-Julas repented, and his repentance was sincere.
"And they disbelieved after their Islam"
They manifested their disbelief after having manifested Islam.
"And they plotted that which they could not attain"
This refers to the assassination of the Messenger of Allah (ﷺ) upon his return from Tabuk. Fifteen of them conspired to push him off his mount into the valley when he ascended the mountain pass at night. ‘Ammar ibn Yasir was holding the halter of his mount, leading it, and Hudhayfah was behind it, driving it. While they were in that state, Hudhayfah heard the sound of camel hooves and the clanking of weapons. He turned around and found masked men. He shouted: "Away! Away, O enemies of Allah!" So they fled.
It is also said: They were hypocrites intending to kill ‘Amir for refuting al-Julas. It is also said: They wanted to crown ‘Abdullah ibn Ubayy, even if the Messenger of Allah (ﷺ) did not consent.
"And they did not resent"
They did not disapprove or find fault.
"Except that Allah and His Messenger had enriched them of His bounty"
When the Messenger of Allah (ﷺ) arrived in Medina, they were in straitened circumstances, neither riding horses nor acquiring spoils. Then they became wealthy through the spoils. Furthermore, a freed slave of al-Julas was killed, and the Messenger of Allah (ﷺ) ordered his blood money to be twelve thousand [dirhams], so he became wealthy.
"So if they repent"
This is the verse at which al-Julas repented.
"In this world and the Hereafter"
[The punishment for them is] through killing and the Fire.
"And among them are those who made a covenant with Allah: 'If He should give us from His bounty, we will surely spend in charity, and we will surely be among the righteous.' But when He gave them from His bounty, they were stingy with it and turned away, while they were refusing. So He penalized them with hypocrisy in their hearts until the Day they will meet Him—because they failed Allah in what they promised Him and because they used to lie."