Imaam As-Sadi (rahimahullaah) stated in ‘Noorul Basaa’ir Wal al-baab fee ahkaam al ‘Ibaadaat Wal Mu‘aamalaat Wal Huqooq Wal Aadaab’ pages 64-65:
When you sit with the people, make humility the sign by which you are recognized. Fear of Allaah should be your shield and giving advice to the servants of Allaah as your constant habit. Be eager to (make) every gathering you in which you sit, to be of goodness- either research into affairs of knowledge or advice on religious matters; either directing (others) towards a general or a particular beneficial affair, or making a mention of the blessings of Allaah; either making a mention of the superior status of praiseworthy manners and good etiquettes or warning against that which is detrimental to the wellbeing of one’s religious or worldly (affairs). The least of this (i.e. your companionship and advice to those you sit with) is that the earnings from their occupations should be by way of permissible (means) and not what is forbidden.
Behave well towards the young, the old and your peers. Deal with each of them in a way they deserve and have respect for the one who deserves to be respected and honoured. Be eager to make your congregation relaxed by way of speech that is appropriate and good, even if that was in relation to the worldly (affairs).
The sensible and determined person achieves abundant goodness through the gatherings of the people and he becomes more beloved to them than all (beloved things). This is because he approaches the people with what they approve (i.e. good) and statements they desire, and the foundation in this is success in taking over control of all the affairs placed before them.
And these affairs (i.e. good advice and companionship) become more emphasized on a journey, because during a journey sitting together is prolonged and the travellers are in need of having someone who revives their hearts with good statements, the news of events and joke–if all of that is truth and not too much–and to assist them with the essential affairs of travel.
Allaah (Glorified be He and free is He from all imperfections) is the one who caused the dissimilarities between His slaves with regards to their manners, their actions and in all of their affairs. Allaah (Alone) is the One Who grants success. [Abridged]