قَصْدًا إِلَى إِغْرَائِهِ وَحَثِّهِ عَلَى زِيَادَةِ التَّظَلُّمِ وَبَثِّ الشَّكْوَى
The aim is to encourage further expression of the grievance.
Ask whether the addressee is already attending. Calling “yā maẓlūm” to summon a distant person may be literal; saying it to someone already recounting a grievance can encourage the person to elaborate.
The same construction does not fix the same rhetorical goal in every setting. Context can shift the function from summoning to inducement without changing the form of address.