Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(And when We gave unto Moses the Scripture), the Torah, (and the Criterion) i.e. We showed in it the lawful and the unlawful, the commands and the prohibitions, as well as other things; it is also said that this means: triumph over Pharaoh, (that you might be led rightfully) guided to avoid error.
And when We gave Moses the book and the discernment.
He gave Moses' folk the discernment outwardly, and He placed the discernment in the inwardness of MuḤammad's folk in addition to their outwardness. The inner discernment is a light in the heart of the friends through which they separate truth from falsehood. It is alluded to in His words, “If you are wary of God, He will appoint for you a criterion” [8:29]. This is why MuṣṬafā said to Wābisa, “Ask for a pronouncement from your heart!” He also said, “Be wary of the perspicacity of the man of faith, for he gazes with the light of God.” When this discernment appears in someone's inwardness, his drinking and aspiration are purified of the dust of others; the walkway of his desire is protected from the debris of customs, the carpet of his days is shaken loose of the opacities of mortal nature, and the eyes of his moment are kept away from the hand of newly arrived things.
Then, things that are reports for others are for him face-to-face vision; what had been the knowledge of certainty becomes the eye of certainty. No newly arrived thing enters existence in the empire without his heart being aware of it. MuṣṬafā was asked if this has a mark. He said, “When light enters the heart, the breast is expanded.” Its mark is that the breast is opened up to the divine light. When the breast is opened up, the aspiration becomes high, every sorrow is comforted, scatteredness turns into togetherness, the carpet of subsistence is spread, the rug of annihilation is rolled up, the corner of heartaches is closed off, and the door to the garden of union is opened. In joy and coquetry, he says with the tongue of the state,
“In the quarter of hope, I have a delightful home,
in the story of passion, I have a delightful problem.
Why do you ask details about my heart, O spirit of the world?
And when We gave to Moses the Scripture, the Torah, and the Criterion (wa’l-furqān is an explicative supplement [of Torah]), that is, the one that discriminates (faraqa) between truth and falsehood and between what is licit and illicit, so that you might be guided, by it away from error.
And when We gave to Moses [the Scripture and the Criterion, so that you might be guided], [when We gave Moses] the heart, the Book of intelligibles, wisdoms and gnostic sciences and the criterion that distinguishes between truth and falsehood, so that you might be guided by the light of Its guidance. If taken according to the first sense [the statement] does not need interpretation.
Allah then said, "Remember My favor on you when I forgave you for worshipping the calf.'' This happened after Musa went to the meeting place with his Lord at the end of that period which was forty days. These forty days were mentioned in Surat Al-A`raf, when Allah said,
(And We appointed for Musa thirty nights and added (to the period) ten (more)) (7:142).
It was said that these days were during the month of Dhul-Qa`dah plus the first ten days in Dhul-Hijjah, after the Children of Israel were delivered from Fir`awn and they safely crossed the sea. Allah's statement,
وَإِذْ ءَاتَيْنَا مُوسَى الْكِتَـبَ
(And (remember) when We gave Musa the Scripture) means, the Tawrah,
(And the criterion) that is that which differentiates between truth and falsehood, guidance and deviation.
(So that you may be guided aright), after escaping the sea, as another Ayah in Surat Al-A`raf clearly stated,
(And indeed We gave Musa ـ after We had destroyed the generations of old ـ the Scripture (the Tawrah) as an enlightenment for mankind, and a guidance and a mercy, that they might remember (or receive admonition)) (28:43).
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
"Furqan": a criterion for distinguishing truth from falsehood. Here it stands for the knowledge and understanding of religion which enables a person to discern between right and wrong, truth and falsehood.
And when We gave to Moses the scripture and the criterion so that you might be guided. The criterion with which this community is distinguished is a light in their hearts by which they differentiate between the truth and falsehood. The Prophet ﷺ said to Wābiṣa “Seek a pronouncement fatwā from your heart.” And he said “Fear the inward perception firāsa of the believer for he sees with the light of God.” And God most high said “If you fear God He will grant you a criterion” [8:29] and that criterion is a legacy for what they have put forward in beautiful works.