Huwa allathee yureekum ayatihi wayunazzilu lakum mina assama-i rizqan wama yatathakkaru illa (surah Ghafir: 13)

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

(40:13) He it is Who shows you His Signs *19 and sends down provision for you from the sky. *20 Yet none takes heed except he who constantly turns to Allah. *21

Huwal lazee yureekum Aayaatihee wa yunazzilu lakum minas samaaa`i rizqaa; wa maa tatazakkaru illaa mai yuneeb

*19) "Signs" imply those Signs which point to the great truth that the Fashioner, Ruler and Administrator of the Universe is One and only One God.
*20) "Sustenance" here implies the rain, for every kind of the sustenance that man gets in the world, depends ultimately on the rainfall. AIlah presents this one single Sign out of His countless Signs, as if to draw the people's attention to the fact: "If you only consider and ponder over the arrangement of this one thing, you will understand that the concept being presented in the Qur'an of the administration of the Universe, is true. This arrangement could exist only it' the Creator of the earth and its creatures and of water and air and the sun and the heat and cold was only One God, and this arrangement could continue to exist for millions and millions of Years with perfect regularity only if the same Eternal God caused it to exist continually. And the One Who brought this arrangement into existence could only be an all-Wise and All-Merciful Lord, Who along with creating men, animals and vegetables in the earth, also created water precisely according to their needs and requirements, and then made these wonderful arrangements for transporting and spreading that water to different parts of the earth with perfect regularity. Now, who can be more unjust than the one who sees all this and yet denies God, or associates some other beings also with Him in Godhead?"
*21) That is, "A person who has turned away from God and whose intellect has been clouded and corrupted by heedlessness or prejudice, cannot learn any lesson from any Sign. He will see with his animal eyes that the winds Blew, the clouds gathered, the lightning thundered and flashed and the rain fell; but his human eyes will never perceive why all this happened, who caused it, and what rights He has on him. "