Al-Faatiha • EN-TAFSIR-IBN-ABBAS
﴿ مَٰلِكِ يَوْمِ ٱلدِّينِ ﴾
“Lord of the Day of Judgment!”
(Owner of the Day of Judgement) the Arbitrator on the Day of Judgement which is the Day of Reckoning and settlement of disputes between created beings, i.e. the Day when people are judged according to their deeds; there is no judge save Him.