This fact is expressed in the following verse: “And it is He who has brought you to life, then He will cause you to die, then bring you to life (again); most surety man is very ungrateful”(22:66)
According to Arabic Kr basically means to cover. example, if a farmer places seeds in the ground, this action is called kufr. The term has been used later for two other meanings which were likened to the root meaning (to cover). These two are:
1. To disbelieve in Allah or his religion.
2. To be unthankful relating to the blessings of Allah (the Almighty).
When a person is given health but misuses it or thinks it is not from Miab, this person is a kafir and if he is very ungrateful he is kaffir. This meaning is meant by the above verse.
Man is often unthankful and ungrateful. He quickly becomes oblivious to the blessings of Allah, the Beneficent. We read in the Glorious Qur'an the story of Korah (Qarun). He had so much money kept in the treasury safes that it took a large number of the keepers of the treasures who had difficulty carrying the keys of his treasury:
“We gave him [Korah] from the treasures to the extent that keys were difficult to be carried by a group of people possessed of great strength.” (28:76)
Korah was invited to be thankful to Allah for innumerable bounties that the Almighty Lord, the Beneficent, bestowed on him. They invited Korah to make use of the blessings and perform good deeds to attain a station of piety and bliss in the next abode (the Hereafter) as God has bestowed upon him His favour. However, the ignorant and arrogant eyes of Korah could not perceive the divine Blessings. In return to this invitation he said: “I have been given this only on account of the knowledge I have.” (28:78)
Korab was finally punished by Allah. Allah made the earth swallow him up and his abode. Those who yearned for his place only the day before began to say: “Ah! (Know) that Allah amplifies and straitens the means of subsistence for whomsoever he pleases of His servants; had not Allah been gracious to us, He would most surely have abased us; Ah! (know) that the ungrateful are never successful” (28:82)