The early scholars said, “julliʿa ʿan qulūbihim”—that is, the dread was cleared away from their hearts. The idiom resembles the expression qarrada al-baʿīr, used when one picks the ticks off a camel. Likewise the verbs taḥarraja, taḥawwaba, taʾaththama, and taḥannatha are employed when a person frees himself from ḥaraj (constraint), ḥūb (sin), ithm (guilt), or ḥanth (perjury).

Ibn Abī Ḥātim related—through al-Ḥasan ibn Muḥammad al-Wāsiṭī, from Yazīd ibn Hārūn, from Sharīk, from Yazīd ibn Abī Ziyād, from Miqsam, from Ibn ʿAbbās—concerning the verse
“until, when the terror is lifted from their hearts,”
that Ibn ʿAbbās said: “When revelation descended, its sound was like the clanging of iron on smooth stone. The inhabitants of the heavens would swoon; then, when the terror was lifted from their hearts, they would say, ‘What has your Lord said?’ The messengers among them would reply, ‘The truth; and He is the Most High, the Most Great.’”

He also reported—through al-Ḥādith ad-Dimashqī, from his father, from Jaʿfar ibn Abī al-Mughīrah, from Saʿīd ibn Jubayr, from Ibn ʿAbbās—regarding the same words:
“The command descends to the lowest heaven with a crash like that of a chain striking rock; all the dwellers of the heavens are seized with fear and ask, ‘What has your Lord said?’ Then they collect themselves and say, ‘The truth; and He is the Most High, the Most Great.’”

In the commentary transmitted by ʿAṭiyyah from Ibn ʿAbbās on the same verse he said: “When Allah revealed to Muḥammad, He summoned the messenger-angel who was to convey the revelation. The angels heard the voice of the Compeller speaking the revelation; when the covering was removed from their hearts they asked what Allah had said. They answered, ‘The truth,’ and they knew that Allah speaks only the truth and that He will certainly fulfill it.” Ibn ʿAbbās added: “The sound of the revelation is like iron striking a smooth rock. When they heard it they fell down in prostration; when they raised their heads they said, ‘What has your Lord said?’ They said, ‘The truth; and He is the Most High, the Most Great.’”

With his chain of transmission, and in the tafsīr of Qatādah—reported by ʿAbd ar-Razzāq from Maʿmar, from him—on the verse
“until, when the terror is lifted from their hearts,”
he said: “When the period of cessation between Jesus and Muḥammad ﷺ had elapsed, the revelation came down with a sound like iron, which alarmed the angels, so Allah said: ‘until, when the terror…’”