(a) The two lovers, the fields and the cloud, need the rain. The field is thirsty for the cloud’s mercy while the cloud suffers from the ailment that it cannot embrace the field, its lover. When rain pours down, both the lovers are satisfied.
(b) Rain is a messenger of mercy between the field and the cloud as it reduces the cloud’s load of water (its ailment) while watering the field (satisfying its thirst), thus showering mercy on both.
© ‘Quench’ means to satisfy thirst.