Justice requires us to remember that when any citizen denies his fellow, saying, “His color is not mine,” or “His beliefs are strange and different,” in that moment he betrays America, though his forebears created this Nation.

Lyndon B. Johnson (1908-1973) American politician, educator, US President (1963-69)

Speech (1965-01-20), Inaugural Address, Washington, D. C.
    (Source)

This is in the formal text of the speech, delivered at the US Capitol building, but a review of the videos (1, 2, 3) shows this as part of a large section of the speech he skipped (from the end of the "AMERICAN COVENANT" section directly to the "AMERICAN BELIEF" section).