The Prophet (ﷺ) said: People who get up from an assembly in which they did not remember Allah will be just as if they had got up from an ass's corpse, and it will be a cause of grief to them.
Sunan Abi Dawud Book 43, Hadith 83
← Previous Hadith The Messenger of Allah (ﷺ) would sit and we would also sit around him. If he got up intending to return, he would take off his sandals or something he was wearing, and his Companions recognising his purpose (that he would return) would stay where they were.

Sunan Abi Dawud Book 43, Hadith 82 Next Hadith → The Prophet (ﷺ) said: If anyone sits at a place where he does not remember Allah, deprivation will descend on him from Allah; and if he lies at a place where he does not remember Allah, deprivation will descend on him from Allah.

Sunan Abi Dawud Book 43, Hadith 84