Ahmed Raza Khan: Mohammed Aqib Qadri:
And when a Noble Messenger from Allah came to them, confirming the Book(s) which they possessed, a group of those who have received the Book(s) flung the Book of Allah behind their backs as if they were totally unaware!
Yusuf Ali:
And when there came to them a messenger from Allah, confirming
what was with them, a party of the people of the Book threw away the Book
of Allah behind their backs, as if (it had been something) they did not
know!
Pickthal:
And when there cometh unto them a messenger from Allah,
confirming that which they possess, a party of those who have received the
Scripture fling the Scripture of Allah behind their backs as if they knew
not,
Courtesy of: 
(PrayerWare)
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