"Then they are returned to Allah, their Master, the Truth." Meaning: their Owner. "The Truth" is one of the names of Allah. "Unquestionably, His is the judgment, and He is the swiftest of reckoners."
Yahya said: I heard one of the Kufans say: Allah will finish the judgment between the creation
﴿ثُمَّ رُدُّوا إِلَى اللَّهِ مَوْلاهُمُ الْحق﴾ يَعْنِي: مَالِكَهُمْ، وَالْحَقُّ: اسْمٌ مِنْ أَسْمَاءِ اللَّهِ ﴿أَلا لَهُ الْحُكْمُ وَهُوَ أسْرع الحاسبين﴾.
قَالَ يحيى:
سَمِعْتُ بَعْضَ الْكُوفِيِّينَ يَقُولُ: يَفْرَغُ اللَّهُ مِنَ الْقَضَاءِ بَيْنَ الْخَلْقِ