Assalaamu alaykum wa rahmatullaahi wa barakaatuhu, Shaykh. It is true that angels look for gatherings where Allaah, The Exalted, is mentioned (and all that is mentioned in the hadiths that speak about this subject takes place). Does the same happen when a person is alone in a room and recites the Quran or listens to the Quran or an Islamic lecture? May Allaah reward you.
All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
Targheeb (encouraging people to do good by mentioning Allah’s promises and rewards) has been proven about assemblies that include types of Thikr(expressions of remembrance of Allah) such as the recitation of the Quran, Tasbeeh (saying Sobhaana Allah [glory be to Allah]), Takbeer (saying Allahu Akbar [Allah is Great]), and other types of remembrance of Allah.
The Prophet said, “Allah has angels who roam the roads looking for those who mention Allah. When they find some people who mention Allah, they call each other, saying, 'Come to the object of your pursuit.' "He [Prophet] added, 'Then the angels encircle them with their wings up to the sky of the world...'" [Al-Bukhaari]
In another hadeeth, the Prophet said, “Allah has mobile (squads) of angels who have no other work (to attend to) but to look for the assemblies of Thikr, and when they find such assemblies in which there is Thikr (of Allah), they sit with them, and some of them surround the others with their wings till the space between them and the sky of the world is filled with them.” [Muslim]
Also, the angels attend the house in which the Quran is recited, whether the reciter is alone or is listening to the recitation of the Quran. Al-Baraa’ ibn ‘Aazib, may Allah be pleased with him, narrated, “A man was reciting Soorah Al-Kahf, and there was a horse tied with two ropes at his side. A cloud overshadowed him, and it began to come nearer and nearer, and his horse began to take fright from it. In the morning, he went and mentioned that to the Prophet and the Prophet said to him, 'That was the tranquility that came down because of the recitation of the Quran.'” [Al-Bukhaari and Muslim]
In Sharh Al-Bukhaari by Ibn Battaal, it reads, “The Prophet said in the hadeeth narrated by Al-Baraa’ about Soorah Al-Kahf, 'That was the tranquility that came down because of the recitation of the Quran.' Once, the Prophet informed about the descent of tranquility, and at another time, he informed us about the descent of the angels. This proves that the tranquility was in that cloud and that it always descends with the angels; and Allah knows best.”
Moreover, the Musannaf by Ibn Abi Shaybah quoting Ibn Seereen, reads, “The house in which the Quran is recited is attended by the angels, and the devils go out of it. It [the house] becomes spacious for those living in it, and its goodness becomes abundant, whereas the house in which the Quran is not recited, it is attended by the devils, and the angels go out of it. It becomes narrow for those living in it and its goodness becomes little.”
On the other hand, Ibn Saabit said:
“Indeed, the houses in which the Quran is recited shine to the people of the sky in the same manner that the sky shines to the people of the earth. Indeed, the house where the Quran is not recited becomes narrow for its people, and it is attended by the devils and the angels flee away from it. Abu Hurayrah used to say, 'If the Book of Allah is recited in a home; it becomes spacious for its people, its goodness becomes abundant, and it is attended by the angels, and the devils go out of it, whereas the house in which the Quran is not recited becomes narrow for its people, its goodness becomes little, and the angels avoid it and the devils attend it.” [Abridged]
Regarding teaching and learning knowledge, listening to it, and studying it, Ibn Hajar stated that it is not included in the assemblies attended by the angels, as he said in Fath Al-Baari:
“From all these sources (i.e. the Islamic texts), we conclude that what is meant by the assemblies of Thikr are the assemblies that include the mention of Allah with the types of Thikr that are mentioned, such as Tasbeeh, Takbeer, and so forth, and the recitation of the Book of Allah, and the supplication for the goodness of this worldly life and of the Hereafter. As regards the issue whether or not reading the Prophetic ahaadeeth, studying and revising Islamic knowledge, and gathering for optional prayers are included in these assemblies, then it is an issue that has to be looked at. It seems that this applies only to the assemblies of mention of Allah, Takbeer, the recitation of the Quran, and the like; even though reading the ahaadeeth and studying Islamic knowledge and discussing it is included under the name of the mention of Allah in general.”