The Jewish Rabbis were entrusted

We have certainly revealed the Torah in which there is guidance and light (details concerning the laws of Allaah). The Ambiyaa, who were obedient to Allaah, judged the Jews with it (the Torah) and the people of Allaah (the pious ones) and the scholars (also judged with it) because they were instructed to preserve Allaah's Book and they were witnesses to it. So do not fear the people but fear Me and do not sell My verses for a small gain (do not distort the verses of the scriptures I reveal for fear of people and to make some money). Whoever does not judge by what Allaah has revealed, then they surely are (behaving like the) Kaafiroon. (Surah 5:44)

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It is clear from the above  Quran Ayat, that the Jewish scholars (Rabbis of the Law) were entrusted to preserved (take care of) the Torah which was given to them. They were give the responsibility to keep the Torah safe.

Let's imagine this scenario:

Suppose you left all your household belongings (furniture, cooker. Fridge etc..) to a storage  company to keep safe until you move into your new property . After you move in to your new premises you go back to the storage company, and find out your household belongings are damaged or changed with other spare parts. Would you blame yourself or storage company? Naturally you'll blame the storage company right?. Why because you entrusted them with your personal belongings and they broke your trust and changed or damaged your personal property.

What if you purchased new furniture's before going to the storage company. What if your whole purpose was to go and tell the company, "I don’t really care of those belongings as I have new and better ones". Did you catch the drift?

If the Torah was entrusted to the Jewish Rabbis to preserve, and instead they distorted the texts. This doesn’t mean the words of Allah Swt has been changed no it only means that the Torah was only given to the Bani Isreal to keep. It was for their use only. If they distort it, change it, then they would be responsible for it since it was for them to keep safe. This doesn’t affect the universal message of Allah Swt. The Quran was meant to come and supersede all Books.

Even Paul in the New Testament makes mentioned of the Jews being entrusted with the word of God : Much in every way! First of all, the Jews have been entrusted with the very words of God. (Roman 3:2)

Allah Swt said he will preserve, guard the Quran. This does not include the previous books as they were given to a certain group or people or nation only, for a certain period of time.

Without doubt only We have revealed the Reminder (the Quraan) and (by carious means) We shall certainly be its protectors (ensuring that it remains unchanged throughout time). (Surah 15:9)

The Jews intentionally concealed words from the Torah. They made SEPARATE SHEETS FOR SHOW! Yet by the Mercy of Allah Swt the Quran was sent as a Guidence to Mankind Alhumdulillah.

 No just estimate of Allah do they make when they say: "Nothing doth Allah send down to man (by way of revelation)" Say: "Who then sent down the Book which Moses brought?- a light and guidance to man: But ye make it into (separate) sheets for show, while ye conceal much (of its contents): therein were ye taught that which ye knew not- neither ye nor your fathers." Say: "(Allah) (sent it down)": Then leave them to plunge in vain discourse and trifling.

And this is a Book which We have sent down, bringing blessings, and confirming (the revelations) which came before it: that thou mayest warn the mother of cities and all around her. Those who believe in the Hereafter believe in this (Book), and they are constant in guarding their prayers. (Surah 6:91-92)