Reminding of some of the etiquettes of the gathering, along with mentioning some of the hadiths indicating this.

The Shaykh : Imam Ahmad narrated in his Musnad from the hadith of Abu Thalhah al-Khushani (may Allah be pleased with him), who said: "When we used to travel with the Prophet (peace and blessings be upon him) and we would stop at a place, we would disperse into the valleys and gorges. One time we traveled with the Prophet (peace and blessings be upon him) and stopped at a place, and we dispersed in it as we always used to disperse." He said to them (may the prayers and peace of Allah be upon him): . Abu Thalhah said: "So after that, whenever we traveled with the Prophet (peace and blessings be upon him), we would gather and some of us would join with others, until if we had sat on a single carpet, it would have been enough for us."
In this hadith, there is the Prophet's (peace and blessings be upon him) concern for gathering the Muslims together in their bodies and persons, and his warning them against dispersing in this manner, even while traveling in the valleys and gorges. The Companions of the Prophet (peace and blessings be upon him) responded to this guidance, so after that, they did not disperse as they had previously, and they would stick together, some with others, until that despite their large number, if they had sat on a single carpet, it would have been enough for them. This dispersing, which occurred only during travel, was not approved by the Messenger of Allah (peace and blessings be upon him); rather, he forbade them from it. So what is the case when the scholars and students of knowledge disperse in their scholarly gatherings? There is no doubt that this dispersing is from the work of Satan, and even more so. Therefore, we remind you, considering that a good portion of you is hoped to be among those responsible for guiding the Ummah and teaching them the Book and the Sunnah. This is from the Sunnah that they should begin by reminding people of, namely gathering them in one gathering, and that they should not remain like this, dispersed, some far from others.
This hadith is supported in its content, which encourages gathering people in the assembly and forbids their dispersing therein, by another hadith narrated by Imam Muslim in his Sahih, that the Prophet (peace and blessings be upon him) entered the mosque and found them dispersed in it, so he said to them (may the prayers and peace of Allah be upon him): meaning: dispersed. So we understand from this hadith that dispersing in the mosque is also, indeed, even more so, not prescribed; rather, they should gather, some with others, and they should be concerned with listening to knowledge and good admonition.
The prohibition of the Messenger (may the prayers and peace of Allah be upon him) of this dispersing is connected to that principle we referred to, that Islam is concerned with rectifying the outward appearance just as it is concerned with rectifying the inward state; because each of them is connected to the other with a close connection that cannot be severed.