Salamualaikum
Dear Scholar I would like to ask based on the Hadith in which Hazrat Umar( R.A) was reading the Torah and the Prophet forbade him.So my question is how come Umar(R.A) was reading the Torah whose language was Arabic and the first Bible came after him?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Apparently, ‘Umar was reading a copy of the Torah translated into Arabic, as the Jews used to translate the Torah into Arabic. Abu Hurayrah said, “The people of the Scripture (Jews) used to recite the Torah in Hebrew and explain it in Arabic to the Muslims. On that, the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said, "Do not believe the people of the Scripture or disbelieve them, but say: {We believe in Allaah and what is revealed to us.}[Quran 2:136].” [Al-Bukhari]

This was explicitly stated in another version of this Hadeeth narrated by Al-Bazzaar on the authority of Jaabir . He said, “‘Umar copied part of the Torah in Arabic, brought it to the Prophet, sallallaahu ‘alayhi wa sallam, and began to read it to him. As he read, the Prophet’s face changed color. One of the men of the Ansaar said, "Woe to you Ibn Al-Khattaab! Can you not see the face of the Messenger of Allaah?’ Thereupon, the Prophet, sallallaahu ‘alayhi wa sallam, said, ‘Do not ask the People of the Book about anything for they will not guide you when they have gone astray. (If you listen to them) You will either disbelieve in what is right or believe in what is false. By Allaah, if Moses had been alive today, he would have been obliged to follow me.’” [Al-Haafith Ibn Hajar said that one of its narrators is Jaabir Al-Ju‘fi and he is a weak narrator] For more benefit, see Fatwa 83344.‏

Allaah Knows best.