It is a lie to say that the area that is now Israel was given in the mandate to the Jews to be their homeland. The Jews were given the right to have a homeland within a certain area, but they were not supposed to make a Jewish state within that area, and Palestinians were also supposed to have their homeland within that area as well, and they were supposed to have a right to self-determination in that area.

Regardless of whether or not Arabs (Muslim or Christian) didn't agree to the partition plan that does not, and did not, give Israel the right to take any more land than what they were given in the partition plan. The only land they were ever given a right to have by any outside authority was the land they were given in the partition plan, and that land was a fraction of the land they now control.