Tafsir of Al-Qalam 68:33

كذلك العذاب

Such is the punishment, meaning, such is the punishment of whoever opposes the command of Allah, is stingy with what Allah has given him and favored him with, withholds the right of the poor and needy, and responds to Allah's blessings upon him with ungratefulness (or disbelief)

ولعذاب اﻻخرة أكبر لو كانوا يعلمون

but truly, the punishment of the Hereafter is greater if they but knew. meaning, this is the punishment in this life, as you have heard, and the punishment of the Hereafter is even harder