The children of Israel did not only believe in Allah but they also entered into a covenant relationship with Allah. The book and the prophethood was given to the seed of Yaqub (jacob). The Covenant and promises of the covenant were given to Abrahim then ishaq (isaac) then it (the covenant inheritance, birth right) was passed to Yaqub (jacob) whom was renamed as Israel and from jacob the inheritance was passed to his 12sons whom became 12tribes (children of israel). Bani Israil (the children of Israel) experienced great salvation from Allah (the plagues in egypt, the red sea split before them that they may walk through as on dry land, The fire of Allah came down on Mt. Sinai and he spoke to them as a nation from the fire) no other nation has Allah done such things as this.
In the covenant of Allah with Bani Israel there was supreme blessings if they obeyed but curses if the rebelled and worshiped strange gods.
Read deuteronomy 28 in Torah (bible)
They went astray and were exiled out of the holy land of Israel and went into middle east and great majority went south into Africa and interior of Africa and were sold into slavery as it was prophecied by prophet musa (moses) in deuteronomy 28.