Jesse Jackson, the legendary civil rights leader and presidential candidate, endorsed Bernie Sanders on Sunday as the Vermont senator fights back against Joe Biden.

Jackson's blessing came ahead of Tuesday's primary in Michigan, a contest he won in his 1988 presidential campaign.

Sanders won Michigan in the 2016 Democratic primary - a victory that shocked rival Hillary Clinton's camp.

Jesse Jackson endorsed Bernie Sanders for president on Sunday; the two men are seen together in Grand Rapids, Michigan

Bernie Sanders and Jesse Jackson peek out at the crowds awaiting them in Grand Rapids ahead of their rally there

Jesse Jackson, arriving for a campaign rally the Vermont senator, said in his endorsement Sanders would heavily consider having a black woman as his running mate

Bernie Sanders waits to be introduced at a campaign rally in Grand Rapids; he is fighting hard to win Michigan, a state that he won in the 2016 Democratic primary

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He has campaigned there heavily to repeat the win and reclaim the frontrunner status from Biden, who surged ahead in the Democratic primary after a strong showing in the Super Tuesday contests.

'The most progressive social and economic path gives us the best chance to catch up and Senator Bernie Sanders represents the most progressive path. That's why I choose to endorse him today,' Jackson said in a statement.

He campaigned for Sanders in Grand Rapids, Michigan, on Sunday. Rep. Alexandria Ocasio-Cortez will campaign for Sanders in Michigan on Sunday also.

Jackson could also be a boon for Sanders in Illinois, which holds its primary on March 17. The reverend has strong ties to Chicago and his son used to represent a section of the city in Congress.

Additionally, Jackson still carries heavy influence in the African American community and could help Sanders combat Biden's strong support among that voting bloc.

'As I think you well know, Jesse has been one of the great civil rights leaders in the modern history of this country,' Sanders said Sunday on ABC's 'This Week.'

Jesse Jackson during the 1988 presidential campaign, when he won Michigan

Jackson's blessing could help Sanders cut in to Joe Biden's support among African American voters

Bernie Sanders told Fox News he would not consider dropping out if he loses Michigan on Tuesday

But Sanders said if he loses the state in Tuesday's primary he's not dropping out of the primary race.

'I certainly would not consider dropping out,' he said on 'Fox News Sunday.'

Sanders said on Sunday that he would not linger in the race if it couldn't be warned but he also noted the next two Tuesdays have big states voting.

'Look, we will fight for every vote that we can, as we’re -- as we try to win this election. I’m not a masochist who wants to stay in the race that can't be won,' he said on ABC's 'This Week.'

'But right now, that's a little bit premature. Let's not determine what will happen on Tuesday, what will happen in future,' he said.

'We have a long, long way to go to the Democratic nomination and we're going to fight for every vote that we can get,' Sanders noted.

Jackson, in his statement announcing his support for Sanders, noted Biden never asked him for his endorsement.

'The Biden campaign has not reached out to me or asked for my support. The Sanders campaign has,' he said in his statement.

He noted the Sanders' campaign responded to his concerns on voting rights, taxes needed on the wealthy, renewing a U.S. Civil Rights Commission, and having a single payer health care plan.

Jackson also noted 'Senator Sanders acknowledges Rev. Jackson's challenge to put an African American woman on the 2020 Democratic presidential ticket and will give it the highest consideration. Senator Sanders has also agreed to make sure that black women are in his cabinet and are at the highest levels throughout his administration should he be elected president.'

Sanders said he is 'proud' of the endorsement.

'What Rev. Jackson understands is that we have to move aggressively to wipe out all forms of racism in this country and we need an economic agenda that speaks to the needs of working people, not just the billionaire class,' he told CNN's 'State of the Union.' 'I think with Rev. Jackson -- I think we got a real boost in our campaign.'