Every year, the world honors Dr. Martin Luther King Jr. for his unwavering commitment to the fight for social justice and racial equity; this year is no different.

On Monday (Jan. 18) — Martin Luther King Jr. Day — Barack Obama and a few other people took to social media to memorialize the civil rights activist, quoting gems from his many speeches and highlighting the work he did to advance social change.

Obama — whose presidency was made possible because of King’s fight — tweeted, “If anyone had a right to question whether our democracy was worth redeeming, it was Dr. Martin Luther King, Jr. Because in the face of billy clubs and lynchings, poll taxes and literacy tests, he never gave in to violence, never waved a traitorous flag or gave up on our country. On #MLKDay, we celebrate his life, but we’re also called to live out his values through service of our own.”

Alexandria Ocasio-Cortez’s tribute cited multiple quotes from the orator. “The problems of racial injustice and economic injustice cannot be solved without a radical redistribution of political and economic power,” read one of her posts.

King helmed and participated in several marches and nonviolent protests in his lifetime, hoping to attain basic civil rights for Black people, including the right to vote. His famous “I Have A Dream” speech, in particular, captured his desire for the equal treatment of Black and white people — something Black Lives Matter protesters are still working toward in modern day. Before and after his 1968 assasination, his social justice work was backed and supported by many, most notably his wife Coretta Scott King who reportedly helped to make Martin Luther King Day possible.

“As you honor my father today, please honor my mother as well,” MLK’s daughter Bernice King asked her followers. “She was the architect of the King Legacy and founder of @TheKingCenter, which she founded less than three months after daddy died. Without #CorettaScottKing, there would be no #MLKDay.”