Praise be to Allah, and may peace and blessings be upon the Messenger of Allah. To proceed:
The texts of the Qur’an and Sunnah indicate that the Prophet Muhammad ﷺ was mentioned in the earlier scriptures, that the prophets, peace be upon them, were given glad tidings of his coming, and that a covenant was taken from them to believe in him and support him if they lived to see his time.
Allah, Most High, says:
“Those who follow the Messenger, the unlettered Prophet, whom they find written in what they have of the Torah and the Gospel, who enjoins upon them what is right, forbids them what is wrong, makes lawful for them the good things, prohibits for them the impure things, and relieves them of their burdens and the shackles which were upon them. So those who believe in him, honor him, support him, and follow the light which was sent down with him—it is they who will be successful.” [Al-Aʿraf: 157]
Ibn Kathir, may Allah have mercy on him, stated in his commentary on this verse that this is a description of the Prophet Muhammad ﷺ in the books of the prophets, and that the prophets gave their peoples glad tidings of his coming and instructed them to follow him, and that his characteristics were known to the scholars among the People of the Book.
There are reports indicating that some People of the Book knew the description of the Prophet ﷺ.
Among them is a report narrated by Imam Ahmad from a Bedouin man who saw the Prophet ﷺ with Abu Bakr and ʿUmar, may Allah be pleased with them. They then passed by a Jewish man who was reading the Torah. The Prophet ﷺ asked the Jewish man to tell him whether he found his description and his mission in his scripture. The man's son replied that they found his description and his mission in their scripture, and he then testified that there is no deity worthy of worship except Allah and that Muhammad is the Messenger of Allah.
It is also authentically reported in Sahih al-Bukhari that ʿAta’ ibn Yasar asked ʿAbdullah ibn ʿAmr ibn al-ʿAs, may Allah be pleased with them, about the description of the Messenger of Allah ﷺ in the Torah. He replied:
“Yes, by Allah, he is described in the Torah with some of the description given in the Qur’an: ‘O Prophet, We have sent you as a witness, a bearer of glad tidings, and a warner, and as a protector for the unlettered. You are My servant and My Messenger. I have named you Al-Mutawakkil…’”
He then mentioned among his characteristics ﷺ that he was neither harsh nor coarse, did not raise his voice in the marketplaces, forgave and pardoned, and that Allah would open through him hearts that were closed, ears that were deaf, and eyes that were blind.
These characteristics are consistent with what was known of the Prophet ﷺ: mercy, excellent character, and calling people to the Oneness of Allah, Most High.
The glad tidings of the Prophet ﷺ were not limited to mentioning his description in the earlier scriptures. Allah, Most High, also informed us that He took a covenant from the prophets to believe in and support a messenger who would come confirming what they already had.
Allah, Most High, says:
“And when Allah took the covenant of the prophets, [saying], ‘Whatever I have given you of Scripture and wisdom, then there comes to you a messenger confirming what is with you, you must surely believe in him and support him.’ He said, ‘Do you affirm and accept My covenant on that condition?’ They said, ‘We affirm it.’ He said, ‘Then bear witness, and I am with you among the witnesses.’” [Aal ʿImran: 81]
Al-Qurtubi, may Allah have mercy on him, mentioned that among the interpretations given by the scholars of tafsir is that the messenger referred to in this verse is Muhammad ﷺ, and that Allah took a covenant from the prophets that they would believe in him and support him if they lived to see his time, and that they would take the same covenant from their peoples.
The fact that the name of the Prophet ﷺ is not found explicitly in a particular copy of the scriptures circulating today does not necessarily negate the original glad tidings concerning him. The Qur’an states that the People of the Book find him written in the Torah and Gospel, while these books have also undergone alteration and changes.
Therefore, the point is not to establish that the name Muhammad ﷺ must appear explicitly in every copy existing today. Rather, the point is that the original glad tidings of the Prophet ﷺ and his description existed in the scriptures that Allah revealed, and that some of this remained according to what Allah willed to remain.
The Noble Qur’an establishes that the Prophet Muhammad ﷺ was mentioned in the Torah and Gospel and that his description was known to some scholars among the People of the Book. The Sunnah and reports also contain evidence that some People of the Book knew his description ﷺ. Allah, Most High, also informed us that He took a covenant from the prophets to believe in and support the messenger who would come after them.
As for the scriptures existing today, they have undergone alteration. Therefore, it is not necessary that the glad tidings concerning the Prophet ﷺ be apparent in all their copies or that his name be explicitly stated in them.
And Allah knows best.