What is the difference between worshipping Allah and worshipping for the sake of reward in the Hereafter, and is he who worships Allah for the sake of the Hereafter considered like him who worships Him for His own sake?

It is better for a Muslim to worship Allah out of obedience, submission, and seeking His countenance. However, there is no harm in considering the reward in the hereafter, because the Shariah has encouraged righteous deeds by mentioning their reward in the afterlife, as seen in the noble verses and hadiths that explain the recompense for those who pray and do good deeds. Indeed, working for Allah while hoping for reward does not contradict sincerity.