In a Sacred hadith, the Prophet (saws) said that Allah (swt) says:

“O My servants, were the first of you and the last of you, the human of you and the jinn of you to be as wicked as the most wicked heart of any one man of you, that would not decrease My dominion in anything. O My servants, were the first of you and the last of you, the human of you and the jinn of you to rise up in one place and make a request of Me, and were I to give everyone what he requested, that would not decrease what I have, any more that a needle decreases the sea if put into it. O My servants, it is but your deeds that I record for you and then recompense you for. So let him who finds good, praise Allah, and let him who finds other than that blame no one but himself.”[1]

Allah as well says:

 وَإِذْ تَأَذَّنَ رَبُّكُمْ لَئِن شَكَرْتُمْ لَأَزِيدَنَّكُمْ ۖ

(And [remember] when your Lord proclaimed, ‘If you are grateful, I will surely increase you [in favor];) (Ibrahim: 7)

Allah (swt) puts believing before gratefulness, because the last is connected with the gifts while believing is connected with the Granter. For the human sees first the giving then he believes in the Giver. Certainly, Allah (swt) is more merciful than all humans because He (swt) is Who created them, definitely not to torture them, hence, whenever man is grateful, Allah (swt) will surely increase him in favour

 

 

[1] Sahih Muslim: The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship, Hadith No. 2577.