Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(And when it is said unto them) i.e. the Jews: (Believe in that which Allah hath revealed) meaning: the Qur'an, (they say: We believe in that which was revealed unto us) i.e. the Torah. (And they disbelieve in that which cometh after it) other than the Torah, (though it is the Truth) i.e. the Qur'an is the Truth (confirming) affirming the Oneness of Allah (that which they possess) of the Book. They said: " O Muhammad! Our forefathers were believers ". (Say) O Muhammad!: (Why then slew ye the Prophets of Allah before, if ye are (indeed) believers?) if your claims are truthful.
And when it was said to them, ‘Believe in what God has revealed, that is, the Qur’ān and other [Books], they said, ‘We believe in what was revealed to us’, that is, the Torah; and (wā, here indicates a circumstantial qualifier) they disbelieve in what is beyond that, what is other than that or what came afterwards, such as the Qur’ān; yet it is the truth (wa-huwa’l-haqqu is a circumstantial qualifier) confirming (musaddiqan, a second circumstantial qualifier for emphasis) what is with them. Say, to them: ‘Why then were you slaying the prophets of God formerly, if you were believers?’ in the Torah and in it you were forbidden to kill them: this address, concerning what their forefathers did, is directed towards those present at the time of our Prophet, on account of their approval of it [that is, of what the forefathers had done].
And when it was said to them, 'Believe in what God has revealed', they said, 'We believe in what was revealed to us', and they disbelieve in what is beyond that; yet it is the truth, confirming what is with them. Say: 'Why then were you slaying the prophets of God formerly, if you were believersḍ'
Although The Jews denied the Truth, They claimed to be Believers!
وَإِذَا قِيلَ لَهُمْ
(And when it is said to them), meaning, the Jews and the People of the Book,
ءَامِنُواْ بِمَآ أَنزَلَ اللَّهُ
(Believe in what Allah has sent down) to Muhammad, believe in and follow him,
قَالُواْ نُؤْمِنُ بِمَآ أُنزِلَ عَلَيْنَا
(They say, "We believe in what was sent down to us.'') meaning, it is enough for us to believe in what was revealed to us in the Tawrah and the Injil, and this is the path that we choose,
وَيَكْفُرونَ بِمَا وَرَآءَهُ
(And they disbelieve in that which came after it).
وَهُوَ الْحَقُّ مُصَدِّقًا لِّمَا مَعَهُمْ
(while it is the truth confirming what is with them) meaning, while knowing that what was revealed to Muhammad,
الْحَقُّ مُصَدِّقًا لِّمَا مَعَهُمْ
(it is the truth confirming what is with them). This means that since what was sent to Muhammad conforms to what was revealed to the People of the Book, then this fact constitutes a proof against them. Similarly, Allah said,
("Why then have you killed the Prophets of Allah aforetime, if you indeed have been believers'').
This means, "If your claim that you believe in what was revealed to you is true, then why did you kill the Prophets who came to you affirming the Tawrah's Law, although you knew they were true Prophets You killed them simply out of transgression, stubbornness and injustice with Allah's Messengers. Therefore, you only follow your lusts, opinions and desires.'' Similarly, Allah said,
(Say (O Muhammad to them): "Why then have you killed the Prophets of Allah aforetime, if you indeed have been believers'').''
وَلَقَدْ جَآءَكُم مُّوسَى بِالْبَيِّنَـتِ
(And indeed Musa came to you with clear proofs) meaning, with clear signs and clear proofs that he was the Messenger of Allah and that there is no deity worthy of worship except Allah. The clear signs -or miracles- mentioned here are the flood, the locusts, the lice, the frogs, the blood, the staff and the hand. Musa's miracles also include parting the sea, shading the Jews with clouds, the manna and quails, the gushing stone, etc.
ثُمَّ اتَّخَذْتُمُ الْعِجْلَ
(yet you worshipped the calf) meaning, as a deity instead of Allah, during the time of Musa. Allah's statement,
(after he left) after Musa went to Mount Tur to speak to Allah. Similarly, Allah said,
And when it was said to them “Believe in what God has revealed” they said “We believe in what was revealed to us” and they disbelieve in what is beyond that; yet it is the truth confirming what is with them. Say: “Why then were you slaying the prophets of God formerly if you were believersḍ” Here the allusion is that when it is said to them “Recognize the truth of what has been shown to you from the decree of [divine] harmony min ḥukm al-wifāq by recognizing the situation and the establishment of proof” their lower selves permit some of what they find ambiguous insofar as it agrees with their self-serving desires but then they disbelieve in what is beyond their worldly concerns. They are distant from the elite and are not considered to be among the masters who have special claim arbāb al-ikhtiṣāṣ.