"And that which they used to ridicule has encompassed them," meaning: the recompense for that ridicule, which is Hell, following the punishment of this world.
Tafsir of Surah Az-Zumar from verse 49 to verse 52.
﴿وحاق بهم﴾ وَجب عَلَيْهِم ﴿مَا كَانُوا بِهِ يستهزئون﴾ أَي: جَزَاء ذَلكَ الِاسْتِهْزَاء وَهِي جَهَنَّم بعد عَذَاب الدُّنْيَا.
تَفْسِير سُورَة الزمر من الْآيَة ٤٩ إِلَى آيَة ٥٢.