فَلَا أُقْسِمُ بِمَا تُبْصِرُونَ
I swear by what you see
وَمَا لَا تُبْصِرُونَ
and what you do not see:
إِنَّهُ لَقَوْلُ رَسُولٍ كَرِيمٍ
it is indeed the speech of a noble apostle
وَمَا هُوَ بِقَوْلِ شَاعِرٍ ۚ قَلِيلًا مَّا تُؤْمِنُونَ
and it is not the speech of a poet. Little is the faith that you have!
وَلَا بِقَوْلِ كَاهِنٍ ۚ قَلِيلًا مَّا تَذَكَّرُونَ
Nor is it the speech of a soothsayer. Little is the admonition that you take!
تَنزِيلٌ مِّن رَّبِّ الْعَالَمِينَ
Gradually sent down from the Lord of all the worlds.
وَلَوْ تَقَوَّلَ عَلَيْنَا بَعْضَ الْأَقَاوِيلِ
Had he faked any sayings in Our name,
لَأَخَذْنَا مِنْهُ بِالْيَمِينِ
We would have surely seized him by the right hand
ثُمَّ لَقَطَعْنَا مِنْهُ الْوَتِينَ
and then cut off his aorta,
فَمَا مِنكُم مِّنْ أَحَدٍ عَنْهُ حَاجِزِينَ
and none of you could have held Us off from him.
وَإِنَّهُ لَتَذْكِرَةٌ لِّلْمُتَّقِينَ
Indeed it is a reminder for the Godwary.
وَإِنَّا لَنَعْلَمُ أَنَّ مِنكُم مُّكَذِّبِينَ
Indeed We know that there are some among you who deny [it].
وَإِنَّهُ لَحَسْرَةٌ عَلَى الْكَافِرِينَ
And indeed it will be a [matter of] regret for the faithless.
وَإِنَّهُ لَحَقُّ الْيَقِينِ
It is indeed certain truth.
فَسَبِّحْ بِاسْمِ رَبِّكَ الْعَظِيمِ
So celebrate the Name of your Lord, the All-supreme.
English translation: Ali Quli Qarai
The closing movement seals the Sura's argument: the reality of the Resurrection rests on the truthfulness of the Qur'an that announces it. "So I swear (fa-la uqsim) by what you see and what you do not see." On the particle la, Tabarsi and Tusi canvass the same four views — a rebuttal of the deniers; an extra emphatic; a negation of the oath (the matter being too clear to need one — Abu Muslim); or the idiom "No, by God..." — Tabarsi and Tusi adding al-Jubba'i's caveat that one may swear only by God, so the oath is by the Lord of the seen and unseen. Al-Mizan takes the oath at face value as by the whole of creation (the unseen and the witnessed), pointedly excluding God's Essence (Qur'anic adab does not rank Creator with creature), and rejects the narrowing readings (creation/Creator, blessings, jinn/men, etc.) as less general than the wording.
On "Indeed it is the word of a noble messenger" (v. 40) the sources divide. Al-Mizan argues from the context — especially v. 44 — that the noble messenger is the Prophet, the verse affirming his messengership against the charges of poetry and soothsaying, the Qur'an being ascribed to him only as the word he conveys from his Sender ("a sending down from the Lord of the worlds," v. 43). Tabarsi and Tusi report both the Prophet (al-Farra', Qatada, al-Hasan) and Gabriel (al-Jubba'i) as candidates. All three explain the i'jaz argument behind vv. 41–42: the Prophet was kept pure of poetry (which "calls to whim") and soothsaying (rhymed saj‘ claiming jinn-revelation), and the Qur'an's very departure from customary speech is the stronger proof of its inimitability; "little do you believe / take heed" rebukes the deniers.
The forgery-rebuttal (vv. 44–47) — "had he fabricated against Us some sayings, We would have seized him by the right hand, then cut from him the aorta (al-watin), and none of you could have withheld Us" — is read by Tabarsi, Tusi and al-Mizan as a threat to the truthful Messenger himself were he to forge against God: they gloss bi-l-yamin as seizing the right hand in humiliation / cutting it off / seizing by sheer power, and al-watin as the heart-cord or aorta (citing al-Shammakh's verse). Al-Mizan stresses (with al-Isra 74–75, al-An'am 88) that this menaces the genuine messenger, so it cannot be turned against the survival of every lying prophet-claimant. Here al-Qummi and al-Burhan preserve the distinctively Shi'i reading — reported strictly as-attributed, not as fact: the "noble messenger" is Gabriel conveying the walaya of 'Ali (al-Kazim via al-Kulayni), the alleged "fabrication" being the Ghadir proclamation ("whoever's master I am, 'Ali is his master"), which God vindicates as "a sending down from the Lord of the worlds," with haqq al-yaqin glossed as 'Ali (al-Qummi, al-Sadiq via Ibn Shahrashub); al-Qummi also reads al-watin lexically as a vein in the back connected with offspring. Finally vv. 48–52 declare the Qur'an "a reminder for the God-fearing," known to be belied by some, "a regret for the disbelievers," and "the certain truth (haqq al-yaqin)" — al-Mizan noting the close mirrors that of al-Waqi'a (same purpose, same sealing oath) — and command "glorify the name of your Lord, the Great." Tusi preserves the tradition that on this verse's revelation the Prophet said, "Put it in your bowing (ruku')," the origin of subhana rabbiya l-'azim; the published Enlightening Commentary closes the Sura with a like cluster of glorification traditions.