In this hadith Muhammed frowned when he heard some verses of Torah to the extent that he even denied Moses teaching if he was there!!!, so I think its either Muhammed was afraid of his followers to know that some texts of Quran were taken from the Torah or he was afraid of his people start reading the Torah in Arabic and find out that there is no prophecy for him in it.
Do you think of any other possible reason?
Abu’l-Darda’ & Musnad Ahmed hadiths:
‘Umar brought some pages of the Tawraat to the Messenger of Allaah (peace and blessings of Allaah be upon him) and said, ‘O Messenger of Allaah, (these are) some pages of the Tawraat which I took from a brother of mine from Bani Zurayq.’ The face of the Messenger of Allaah (peace and blessings of Allaah be upon him) changed, and ‘Abd-Allaah ibn Zayd – the one who was shown the Adhaan in a dream – said: ‘Have you gone mad? Do you not see [the expression] on the face of the Messenger of Allaah (peace and blessings of Allaah be upon him)?’ ‘Umar said: ‘We are content with Allaah as our Lord, with Islam as our religion, with Muhammad as our Prophet and with the Qur`aan as our guide. The Messenger of Allaah (peace and blessings of Allaah be upon him) relaxed and said: ‘By the One in Whose hand is the soul of Muhammad, if Moosa were among you, and you followed him and left me, you would go far astray. You are my share among the nations and I am your share among the Prophets.’
جاء عمر بن الخطاب إلى النبي صلى الله عليه وسلم فقال يا رسول الله إني مررت بأخ لي من بني قريظة فكتب لي جوامع من التوراة ألا أعرضها عليك قال فتغير وجه رسول الله صلى الله عليه وسلم قال عبد الله يعني ابن ثابت فقلت له ألا ترى ما بوجه رسول الله صلى الله عليه وسلم فقال عمر رضينا بالله تعالى ربا وبالإسلام دينا وبمحمد صلى الله عليه وسلم رسولا قال فسري عن النبي صلى الله عليه وسلم وقال والذي نفس محمد بيده لو أصبح فيكم موسى ثم اتبعتموه وتركتموني لضللتم إنكم حظي من الأمم وأنا حظكم من النبيين