﴿ ٱلْمُلْكُ يَوْمَئِذٍ ٱلْحَقُّ لِلرَّحْمَٰنِ ۚ وَكَانَ يَوْمًا عَلَى ٱلْكَٰفِرِينَ عَسِيرًۭا ﴾

“on that Day [it will become obvious to all that] true sover­eignty belongs to the Most Gracious [alone]: hence, a Day of distress will it be for all who deny the truth,”

(The Sovereignty) judgement (on that day will be the True (Sovereignty)) justice (belonging to the Beneficent One, and it will be a hard day for disbelievers) the hardship of that Day is very severe on them.