Q: There is a recurrent habit among the employees in general and teachers in particular that upon the arrival of a new teacher or the transfer of one to another school, they collect money and make a banquet to welcome the newcomer and bid farewell to the teacher who will quit the place. It appears to us that this is a good habit, for it does not contradict the rulings of Shari`ah (Islamic Law). However, the problem starts when some teachers speak about a certain teacher because he did not share with them in this banquet or attend it. As such, they blame and speak ill of him, because, according to their viewpoint, he neglected his social duty and due participation in a good habit practiced by all people. Furthermore, they say that people have acknowledged these habits long ago and the religion of Islam permits taking `Urf (custom) into consideration and acting accordingly in certain matters.I now have two questions: 1- Does people's observance of certain good habit render it obligatory? 2. Is there anything in Shari`ah called "social duty" that if one does not abide by, will be blamed and dispraised?Please, examine the matter in detail, as disputes arose among some teachers when some maintain persistently that conventional acts (Part No. 26; Page No. 143) are obligatory to practice.