Tafsir: Al-Furqan 25:50

وَلَقَدْ صَرَّ‌فْنَاهُ بَيْنَهُمْ (And We have distributed it (the water) among them - 25:50). The verse says that We keep rotating the rainfall, that is, it sometimes falls in one locality and sometimes in another. Then sometimes a locality receives in one year more rain and in subsequent years less. Sayyidna ` Abdullah Ibn ` Abbas ؓ says that the presumption of some people that the quantity of rains varies from year to year is not really correct. In fact the aggregate amount of water sent down to the world (at macro-level) is equal every year. However, according to Allah's will, its allocation for different territories may change from year to year. Sometimes the quantity of water is curtailed for a specific habitation as a punishment and warning for it, and sometimes the quantity of rain is increased for a particular population, again as a punishment for their misdeeds. Thus the water that was a blessing in its origin turns into a torment for the people who are ungrateful and disobedient.