Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(Those unto whom We gave the Scripture) those unto who We gave the knowledge of the Torah, i.e. 'Abdullah Ibn Salam and his followers (recognise (him)) Muhammad through his traits and description (as they recognise their sons. Those who ruin their own souls) through losing this world and the Next, i.e. Ka'b Ibn al-Ashraf and his followers (will not believe) in Muhammad or the Qur'an.
Those to whom We have given the Scripture recognise him, that is, Muhammad (s), by the descriptions of him in their Scripture, as they recognise their sons; those, of them, who have forfeited their own souls do not believe, in him.
(Whatever mercy, Allah may grant to mankind, none can withhold it, and whatever He may withhold, none can grant it thereafter) 35:2. It is recorded in the Sahih that the Messenger of Allah used to supplicate,
(O Allah, there is none Who can avert what You grant or give what You deprive, and no fortune ever helps the fortunate against You.) This is why Allah said,
وَهُوَ الْقَاهِرُ فَوْقَ عِبَادِهِ
(And He is the Irresistible, above His servants,) meaning, to Him the necks are subservient, the tyrants humble before Him and He has complete control over all things. The creatures have all bowed to Allah and are humbled before His grace, honor, pride, greatness, highness and ability over all things. The creatures are insignificant before Him, for they are all under His irresistible decision and power,
(and He is the All-Wise,) in all His actions,
(Well-Acquainted with all things.) Who places everything in its rightful place, grants and favors whomever deserves His favor. Allah said next,
قُلْ أَىُّ شَىْءٍ أَكْبَرُ شَهَـدةً
(Say: "What thing is the most great in witness'') or what is the greatest witness,
قُلِ اللَّهِ شَهِيدٌ بِيْنِى وَبَيْنَكُمْ
(Say: "Allah (the Most Great!) is Witness between you and I'') for He knows what I brought you and what you will answer me with,
(But those of the sects that reject it, the Fire will be their promised meeting place.) 11:17 Ar-Rabi` bin Anas said, "Those who follow the Messenger of Allah ought to call to what the Messenger of Allah called to and warn against what he warned against.'' Allah said next,
(Say: "Only He is God, alone, and truly I am innocent of what you join in worship with Him.'')
People of the Book Recognize the Prophet Just as They Recognize Their Own Children
Allah says, the People of the Book know what you brought them, O Muhammad, as they know their own children. This is because they received good news from the previous Messengers and Prophets about the coming of Muhammad, his attributes, homeland, his migration, and the description of his Ummah. Allah said next,
الَّذِينَ خَسِرُواْ أَنفُسَهُم
(Those who have lost (destroyed) themselves) and thus incurred the ultimate loss,
فَهُمْ لاَ يُؤْمِنُونَ
(will not believe.) in this clear matter. A matter about which the previous Prophets gave good news, and a matter extolled about in ancient and modern times. Allah said next,
(And who does more wrong than he who invents a lie against Allah or rejects His Ayat) meaning, there is no person more unjust than he who lies about Allah and claims that Allah has sent him, while Allah did not send him. There is no person more unjust than he who denies Allah's proofs, signs and evidences,
إِنَّهُ لاَ يُفْلِحُ الظَّـلِمُونَ
(Verily, the wrongdoers shall never be successful.) Surely, both of these people will never acquire success, whoever falsely claims that Allah sent him and whoever refuses Allah's Ayat.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
That is. "Allah is a witness that I have been appointed a Messenger by Him and whatever I say is from Him."
Mere guess-work or speculation does not suffice for testifying to anything: none can testify to a thing with certainty without the necessary knowledge about it. The question implies: "Do you really have the knowledge that there is any other Sovereign with authority than Allah, Who is worthy of service and worship?"
That is, "You may, if you so like, give false testimony without any knowledge, but, as for me, I cannot give such a testimony."
It means that those, who possess the knowledge of revealed Books, know it for certain that there is only One God, Who has no partner in His Godhead. Therefore they can discern the right creed about Allah from among many different kinds of other creeds' and theories about Godhead, just as any person can identify his own child from among many thousands of other children.
"False allegation" is the claim that there are many other partners with Allah in His Godhead who have divine attributes and powers and are thus worthy of worship. It is also false to allege that Allah Himself has made such and such His special courtiers and has enjoined (or at least approved) that Divine attributes should be ascribed to them and that they should be treated with reverence, like Allah.
"Allah's Signs" are all those signs that point to the fact that there is only One God in the universe and that all others are His servants. These signs are spread all over the universe. They are found in the person of man himself and in the character and the great achievements of the Prophets and in the revealed Books. That is why the one, who, in the presence of all these "Signs," ascribes Divine attributes to others and considers them worthy of Divine rights, is in fact guilty of gross iniquity. It is indeed a great injustice that one should ascribe such Divine attributes to others without any evidence, knowledge, observation and experience merely on the basis of guess-work or the traditions of the forefathers. As a result of this false creed, he does injustice to Truth, to Reality, to his own self and to everything and everyone he deals with in this universe.