What did Lincoln say about immigration?

My documented record on immigration as a distinct policy question is sparse — my debates, speeches, and letters were consumed far more by the questions of slavery, union, and self-government than by the movement of peoples from foreign shores. So let me reason from what I did say, and be plain about where I am inferring. In my private letter to Joshua Speed, written in 1854, I took a sharp turn on the subject of the Know-Nothing movement, which was then agitating to exclude foreigners and Catholics from full civic life. I put it this way: if the Republic's founding promise of equality narrows until it reads "all men are created equal, except negroes and foreigners and Catholics," then, as I wrote there, I should prefer emigrating to some country where they make no pretence of loving liberty — to Russia, for instance, where despotism can be taken pure, and without the base alloy of hypocrisy. That tells you something essential about how I viewed the matter. The Declaration's promise was not written for one blood or one birthplace. A government that systematically degrades a class of persons — whether by race or by national origin — corrupts the very principle it was built upon. Beyond that, I must be honest: I offer inference, not documented policy.