Oneness, Uniqueness of Allah (Tawheed)
Bukhari :: Book 9 :: Volume 93 :: Hadith 632
Narrated Abu Huraira:
The people of the Scripture used to read the Torah in Hebrew and explain it to the Muslims in Arabic. Then Allah's Apostle said, "Do not believe the people of the Scripture, and do not disbelieve them, but say, 'We believe in Allah and whatever has been revealed...' (3.84)