Jinnah: Bengali Muslims are from outside

In Dhaka (Dacca), addressing a public meeting, March 21, 1948, Jinnah tried to calm the apprehensions of the East Pakistanis about the official language, Urdu.  He blamed the "certain amount of excitement over the question of whether Bengali or Urdu shall be the State language of this Province and of Pakistan" on the enemies of Pakistan, who were seeking to foment provincialism.

As long as you do not throw off this poison [of provincialism] in our body politic, you will never be able to weld yourself, mould yourself, galvanize yourself into a real true nation.   What we want is not to talk about Bengali, Punjabi, Sindhi, Baluchi, Pathan and so on.  They are of course units.  But I ask you: have you forgotten the lesson that was taught to us thirteen hundred years ago? [i.e., Islam]  If I may point out, you are all outsiders here.  Who were the original inhabitants of Bengal—not those who are now living.  So what is the use of saying "we are Bengalis, or Sindhis, or Pathans, or Punjabis". No we are Muslims.

[emphasis added.  Quote from Speeches, Statements & Messages of the Quaid-e-Azam, Volume IV, collected and edited by Khurshid Ahmad Khan Yusufi.]