Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
Allah then mentions the covenant He undertook with them, saying (And when We made a covenant with you) took your consent (and caused the Mount to tower above you) pulled out and fixed high above your heads the mountain for taking the covenant: (Hold fast that which We have given you) comply with what We have given of the scripture in earnestness and diligence, (and remember that which is therein) of reward and chastisement, and recollect what is in it of the lawful and unlawful, (that ye may ward off (evil)) in order that you may ward off Allah's wrath and torment and so that you may obey Him.
And, mention, when We made a covenant with you, your pledge to act according to what is in the Torah, and We, had, raised above you the Mount, which We uprooted from the earth [and placed] above you when you refused to accept it [sc. the Torah], and We said, ‘Take forcefully, seriously and with effort, what We have given you, and remember what is in it, acting in accordance with it, so that you might preserve yourselves’, from the Fire or acts of disobedience.
And when We made a covenant with you, that is, your former covenant or [your] next one, taken from them in the Torah or [taken from them] on the basis of rational proofs, to affirm the Unity of the acts and the attributes, and We raised above you the Mount, the mountain of the brain to enable [you] to understand and accept meanings, and We said: 'Take, that is, accept, forcefully what We have given you, of the Torah or [of] the Distinguishing Book of the Intellect, [accept it] with earnestness, and remember what is in it, heed what the wisdoms, gnoses, sciences and [divine] laws, so that you might preserve yourselves', so that perhaps you might guard against [succumbing to] associating [others with God], ignorance and wickedness.
Allah reminded the Children of Israel of the pledges, covenants and promises that He took from them to believe in Him alone, without a partner, and follow His Messengers. Allah stated that when He took their pledge from them, He raised the mountain above their heads, so that they affirm the pledge that they gave Allah and abide by it with sincerity and seriousness. Hence, Allah's statement,
(And (remember) when We raised the mountain over them as if it had been a canopy, and they thought that it was going to fall on them. (We said): "Hold firmly to what We have given you (Tawrah), and remember that which is therein (act on its commandments), so that you may fear Allah and obey Him.'') (7:171).
The mount mentioned here is At-Tur, just as it was explained in Surat Al-A`raf, according to the Tafsir of Ibn `Abbas, Mujahid, `Ata', `Ikrimah, Al-Hasan, Ad-Dahhak, Ar-Rabi` bin Anas and others. This is more obvious. There is another report from Ibn `Abbas saying; `The Tur is a type of mountain that vegetation grows on, if no vegetation grows on it, it is not called Tur.' And in the Hadith about the trials, Ibn `Abbas said; "When they (the Jews) refused to obey, Allah raised the mountain above their heads so that they would listen.''
Al-Hasan said that Allah's statement,
خُذُواْ مَآ ءَاتَيْنَـكُم بِقُوَّةٍ
(Hold fast to that which We have given you) means, the Tawrah. Mujahid said that the Ayah commanded, "Strictly adhere to it.'' Abu Al-`Aliyah and Ar-Rabi` said that,
وَاذْكُرُواْ مَا فِيهِ
(and remember that which is therein) means, "Read the Tawrah and implement it.'' Allah's statement,
(Then after that you turned away. Had it not been for the grace of Allah) means, "Yet, after the firm pledge that you gave, you still deviated and broke your pledge'';
فَلَوْلاَ فَضْلُ اللَّهِ عَلَيْكُمْ وَرَحْمَتُهُ
(Had it not been for the grace and mercy of Allah upon you), meaning, by forgiving you and by sending the Prophets and Messengers to you,
لَكُنتُم مِّنَ الْخَـسِرِينَ
(Indeed you would have been among the losers) meaning, in this life and the Hereafter due to their breach of the covenant.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
The way this incident has been described at different places in the Qur'an, shows that it was at that time a well known incident among the Israelites, but now it is difficult to understand and know what actually happened. One may, however, understand that at the time of making the covenant at the foot of the mountain a dreadful situation was created and it so appeared that the mountain was going to fall upon them. A similar scene has been depicted in Surah AI-A'raf, VII: 171. (Please see E.N. 132 of VII, Al-A'raf) Although its description in the Bible is a little different from that of the Talmud, it depicts the scene very vividly: "And mount Sinai was altogether on a smoke, because the Lord descended upon it in fire: and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly." (Exodus, 19: 18.) "And all the people saw the thunderings, and the lightnings, and the noise of the trumpet, and the mountain smoking : and when the people saw it, they removed, and stood afar off. And they said unto Moses, Speak thou with us, and we will hear : but let not God speak with us, lest we die." (Exodus, 20 :1819).
And when We made a covenant for you and We raised above you the mount “Take forcefully what We have given you and remember what is in it so that you might preserve yourselves.” Then you turned away thereafter and but for God's bounty and His mercy toward you you would have been among the losers. He سبحانه made a covenant with all responsible beings and some responded willingly because He made Himself known to them and they declared His unity fa-waḥḥadūhu. Other people responded unwillingly because He veiled them so they did not want to recognize Him fa-jaḥadūhu. There is no proof more powerful than the eyewitnessing of the mount Ṭūr He raised above them which was a mountain jabal but they lacked the light of inner sight baṣīra and so the witnessing of physical vision baṣar did not benefit them. Then you turned away thereafter that is you returned to disobedience after witnessing the signs with your own eyes. If not for His decree in granting respite and His forbearance through acts of grace He would punish you without delay and cause a great misfortune to descend upon you and your deeds would be entirely a loss.