Allah the Almighty says:
“And He giveth you of all ye ask of Him, and if ye would count the bounty of Allah ye cannot reckon it. Lo! man is verily a wrong-doer, an ingrate.” (14:34)
“And if ye would count the favour of Allah ye cannot reckon it. Lo! Allah is indeed Forgiving, Merciful.” (16:18)
“And He giveth you of all ye ask of Him, and if ye would count the bounty of Allah ye cannot reckon it. Lo! man is verily a wrong-doer, an ingrate.” (14:34)
Ali Ibn Abi Talib, may Allah be pleased with him, said:
Blessings are inextricably linked to gratitude.
And gratitude is linked to increase.
Thus, the increase from Allah will not cease,
So long as the servant’s gratitude does not cease.
Al-Hasan al-Basri, may Allah have mercy on him, said:
Indeed, Allah the Almighty grants the enjoyment of blessings to whom He wills;
But if one does not show gratitude for them, He turns them into a torment.
For this reason, they used to call gratitude "the preserver,"
Because it preserves the blessings one already possesses,
And "the attractor," because it brings about the blessings one has yet to attain.