Walaqad sarrafnahu baynahum liyaththakkaroo faaba aktharu annasi illa kufoora (surah Furqan: 50)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(25:50) We present the same phenomenon over and over again before them *64 so that they may learn a lesson from it; but most people decline to adopt any other attitude than of disbelief and ingratitude. *65

Wa laqad sarrafnaahu bainahum li yazzakkaroo fa abaaa aksarun naasi illaa kufooraa

*64) "We present...before them" may have three meanings: (1)"We have cited the phenomenon of rainfall over and over again in the Qur'an in order to make plain to them the Reality."
(2) "We are time and again showing them the wonderful phenomenon of the heat and drought, seasonal winds and clouds, rainfall and its lifeproducing effects."
(3) "We go on changing the system of the distribution of rainfall throughout the , world year after year, so that the same place does not receive the same amount of rainfall every time: sometimes a place is left completely dry, another has more or less of rainfall than usual, while some other is flooded with rain water. They see all these different phenomena with their countless different results in their daily life."
*65) The verse means to impress that the wonderful system of rainfall is by itself a proof of the existence of Allah, of One Lord of the universe, and of His attributes. Its wonderful distribution during the year and over different parts of the earth is a clear proof that there is an All-Wise Designer. But the obdurate disbelievers do not learn any lesson from it, and persist in their ingratitude, though this has been cited in the Qur'an repeatedly for this purpose.
It is also a proof of the life-after-death, for the disbelievers themselves see and again that rainfall brings to life dead land year after year. This clearly that Allah has the power to bring the dead back to life, but the disbelievers it time proves do not learn any lesson from it and persist in their irresponsible ways .
If verse 48 is taken in the metaphorical sense, the "pure water" of rain will mean the blessings of Prophet hood. Human history shows that whenever this blessing as been sent down, ignorance has been replaced by knowledge, injustice by justice and wickedness by righteousness. The coming of Prophets has always proved to be the harbinger of a moral revolution. But only those who accepted their guidance benefited from it. This is the lesson of history, yet the disbelievers reject it because of their ingratitude.