It is He, Who shows you His Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) and sends down (rain with which grows) provision for you from the sky. And none remembers but those who turn (to Allah) in obedience and in repentance (by begging His Pardon and by worshipping and obeying Him Alone and none else).
So, call you (O Muhammad SAW and the believers) upon (or invoke) Allah making (your) worship pure for Him (Alone) (by worshipping none but Him and by doing religious deeds sincerely for Allah’s sake only and not to show-off and not to set up rivals with Him in worship). However much the disbelievers (in the Oneness of Allah) may hate (it).
Chapter 40 Ghāfir : Verses 13-14
Allah demonstrates His power to His servants
(It is He Who shows you His Ayat) means, He demonstrates His power to His servants through the mighty signs which they see in His creation, above and below, which indicate the perfection of its Creator and Originator.
(and sends down provision for you from the sky.) this refers to rain, through which crops and fruits are brought forth, which with their different colors, tastes, fragrances and forms are a sign of the Creator. It is one kind of water, but by His great power He makes all these things different.
(And none remembers) means, no one learns a lesson or is reminded by these things, or takes them as a sign of the might of the Creator,
(but those who turn in repentance.) which means, those who have insight and turn to Allah, may He be blessed and exalted.
The Believers are commanded to worship Allah Alone no matter what Their Circumstances
(So, call you upon Allah making religion sincerely for Him, however much the disbelievers may hate.) This means, worship Allah and call upon Him alone in all sincerity. Do not be like the idolators in conduct and beliefs. Imam Ahmad recorded that after ending every prayer, `Abdullah bin Az-Zubayr used to say: “There is no (true) God except Allah Alone with no partner or associate, His is the dominion and praise, for He is able to do all things; there is no strength and no power except with Allah; there is no (true) God except Allah and we worship none but Him; to Him belongs the blessings and the virtue and good praise; there is no (true) God except Allah, we worship Him in all sincerity even though the disbelievers may hate that.” He said, “The Messenger of Allah used to say Tahlil with this after every prayer.” Something similar was also recorded by Muslim, Abu Dawud and An-Nasa’i. It was reported in Sahih from Ibn Az-Zubayr, may Allah be pleased with him, that the Messenger of Allah used to say the following after the prescribed (obligatory) prayers:
(There is no (true) God except Allah Alone with no partner or associate, His is the dominion and praise, for He is able to do all things; there is no strength and no power except with Allah; there is no (true) God except Allah and we worship none but Him; His is the blessing and virtue and good praise; there is no (true) God except Allah, we worship Him in all sincerity even though the disbelievers hate that.)