To whom does "Lo Sischaten bam" refer?
Yevamos, 76a: It is referring to the seven nations after they have converted. 1
R. Shimon (Yevamos 23a): It applies to all Nochri nations (before conversion
Yevamos Ibid.): Because before they have converted, Chitun (marriage) with a Nochris is not applicable. See also Torah Temimah, note 5.