And they did not appraise Allah with true appraisal when they said, (6:91)

Almuntakhab Fi Tafsir Alquran Alkarim

And they* did not credit Allah with the attributes asserted as His own; they failed to ponder His marvels crediting His Omnipotence. They said: Never did Allah disclose divine knowledge to a human being nor did He admit discourse directly or indirectly to His Omnipotence and Authority. Ask them; Who then had sent down the Book you knew that Mussa presented to his people, the Book flowing forth with illumination and enlightenment to illuminate the intellect of mankind; the Book the Jews divided and again broke up into subdivisions and published the parts they planned to disclose and concealed the many parts which would publish their shame and their immorality; the Book which imparted to them divine knowledge and acquainted them intellectually with facts neither they nor their fathers had ever known. Is it not Allah! Let them Muhammad drown themselves in the nonsensical and engage in amusement which is the happiness of those who cannot think. * The Meccan Infidels and the Jews

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(6:91) They did not form any proper estimate of Allah when they said: 'Allah has not revealed anything to any man.' *59 Ask them: 'The Book which Moses brought as a light and guidance for men and which you keep in bits and scraps, some of which you disclose while the rest you conceal, even though through it you were taught that which neither you nor your forefathers knew -who was it who revealed it?' *60 Say: 'Allah!'- and then leave them to sport with their argumentation.

And they did not appraise Allah with true appraisal when they said, meaning

*59). In the light of the foregoing discussion and commentary, it is quite evident that this statement comes from the Jews. Since the Prophet (peace be on him) had asserted that he was a Prophet and that a Book had been revealed to him, the unbelieving Quraysh and other polytheists of Arabia naturally used to approach the Jews and the Christians - who believed in the Prophets and in the Scriptures - and tried to solicit a candid answer from them as to whether God's words had indeed been revealed to Muhammad (peace be on him). Whatever answer they gave was then disseminated on all sides by the active opponents of the Prophet (peace be on him) in order to create revulsion against Islam. This is the reason for mentioning, and then refuting, this statement by the Jews, which had been used by the opposition as an argument against Islam.
One might wonder how a Jew, who believes in the Torah as a revealed Book of God, could say that God had revealed nothing to anyone. At times blind obstinacy and bigotry cause people to resort to arguments which strike at the roots of their own belief. These people were bent upon denying the prophethood of Muhammad (peace be on him), and this fanaticism had come to dominate them so much that they went so far as to deny the very institution of prophethood.
To say that peopte have not formed any proper estimate of God means that they have erred grossly in assessing His wisdom and power. Whoever says that God did not reveal knowledge of Reality and the code for man's guidance has fallen into one of two errors. Either he considers it impossible for man to become the recipient of God's revelation, and this constitutes a gross misjudgement of God's power, or he thinks that even though God has equipped man with intelligence and with the power to act as he chooses, He has nevertheless made no arrangement for his guidance, but has left him in this world altogether unguided and thus conferred upon him the right to behave in any way he likes. This is obviously a misjudgement of God's wisdom.
*60). The revelation of the Torah to Moses (peace be on him) is adduced by way of evidence since the Jews, to whom this response is addressed, believed that it had been revealed. It is obvious that their recognition of the Torah as the Book revealed to Moses negated their standpoint that God had never revealed anything to any human being. Their belief in the Torah at least proved that revelation to man is possible, and had actually taken place.
 

And they did not appraise Allah with true appraisal when they said, meaning in Urdu

ان لوگوں نے اللہ کا بہت غلط اندازہ لگایا جب کہا کہ اللہ نے کسی بشر پر کچھ نازل نہیں کیا ہے ان سے پوچھو، پھر وہ کتاب جسے موسیٰؑ لایا تھا، جو تمام انسانوں کے لیے روشنی اور ہدایت تھی، جسے تم پارہ پارہ کر کے رکھتے ہو، کچھ دکھاتے ہو اور بہت کچھ چھپا جاتے ہو، اور جس کے ذریعہ سے تم کو وہ علم دیا گیا جو نہ تمہیں حاصل تھا اور نہ تمہارے باپ دادا کو، آخر اُس کا نازل کرنے والا کون تھا؟ بس اتنا کہہ دو کہ اللہ، پھر اُنہیں اپنی دلیل بازیوں سے کھیلنے کے لیے چھوڑ دو