Allah.

فَبِأَيِّ آَلَاءِ رَبِّكُمَا تُكَذِّبَانِ

(55:23) Which of the wonders of your Lord’s power will you twain – you men and jinn – then deny?

وَإِذْ تَأَذَّنَ رَبُّكُمْ لَئِنْ شَكَرْتُمْ لَأَزِيدَنَّكُمْ وَلَئِنْ كَفَرْتُمْ إِنَّ عَذَابِي لَشَدِيدٌ

(14:7) And remember also that your Lord forewarned, `If you be grateful I will increase My favours on you, and if you be ungrateful (you should know that) My chastisement is severe indeed'!"

sometimes i forget. how do i be a grateful servant?