«فَسَقَى دِيَارَكَ غَيْرَ مُفْسِدِهَا»
May the rain water your dwellings without ruining them.
The initial prayer asks for beneficial rainfall, but rain may also damage habitations when excessive. The added phrase «غَيْرَ مُفْسِدِهَا» blocks that unintended possibility. The wish is not merely for rain, but for rain that benefits rather than destroys. This protective qualification exemplifies the purpose of iḥtirās.