The historical figure known for the statement, "Injustice anywhere is a threat to justice everywhere," is Martin Luther King Jr.. This quote, found in his "Letter from Birmingham Jail," emphasizes the interconnectedness of justice and the necessity of fighting against injustice in any form. King's commitment to civil rights and social justice through nonviolent protest fundamentally shaped the American civil rights movement. His powerful words continue to resonate, reminding us of our shared responsibility to advocate for equality and challenge discrimination wherever it occurs.