their flocks]," meaning: they prevent their sheep from mixing with the sheep of the people. "He said" to them, Musa: "What is your affair?" meaning, what is your situation? "They said: We do not water until the shepherds depart [their flocks]," meaning: until the people have finished watering, then we follow after them [to take] what remains of their water; this is the explanation of al-Hasan.

Muhammad said: Whoever reads "yusdir" (until they return the flocks) with a damma on the ya and a kasra on the dal, the meaning is: we are not able to water until the shepherds return their sheep after they have finished drinking. And al-ri'a' (shepherds) is the plural of ra'in (shepherd).