True Happiness
Imām Ibn Taimiyyah, may Allāh have mercy on him, said:
Indeed, enjoyment, joy, happiness, good times, and a pleasure that isn’t possible to express in words [comes] only through having knowledge of Allāh, Almighty and Majestic, singling Him out in worship, and believing in Him [in our hearts and through our speech and actions].
Majmūʿ Al-Fatāwá, vol. 28, p. 31.