You can read all about Douglass's and Truth's opposing experiences and viewpoints in the Key Player Analysis for Frederick. Their little contretemps over the role of God in abolition has been immortalized on Sojourner's gravestone, which asks, "Is God dead?" (Source)
Basically, Frederick D. advocated violence. And our lady Truth thought that the peace needed to be kept.
Both were passionate, driven seekers of equal rights with similarly grim early lives, but those first few years post-escape cemented their different strategies. Frederick was welcomed by the abolitionist cause for his strong oral and writing skills, which focused strongly on the Black man, directly opposing the message in "Ain't I a Woman?"
Sojourner, on the other hand, was taken in by people of faith and continued to have experiences that reaffirmed her beliefs. That faith was foundational to her speaking style. Despite their difference, both were serious movers and shakers toward disrupting the status quo. We'd definitely like to shake both their hands.
On first blush, Harriet Tubman and Sojourner Truth look like sisters from a different mister. Both were born into slavery. Both escaped. Both turned right back around and worked to end slavery.
That's where they start to differ. Sojourner spoke, preached, and generally worked on stage in the abolitionist movement. Harriet was more of a behind the scenes type. She was arguably the most successful conductor on the Underground Railroad, physically risking her life to shepherd escaped slaves to safety.
She and Sojourner shared a devout faith that God would help end the injustice of slavery, although Harriet actually worked with John Brown, who was a bit too violent (read: way too violent) for Sojourner Truth.
Years after slavery was abolished, the fight for equal rights continued. Just check out the 1960s. (And the 1910s, the 1940s, the 1950s—you get the point).
Just like Sojourner Truth, Rosa Parks was a mild-mannered but firm believer in being treated fairly. They both had incidents of violence against them when using public transportation "incorrectly"— Rosa's 1955 act of defiance against the man, in this case Jim Crow laws, echoed Sojourner's earlier protest (read all about it in our Brain Snacks).
Rosa's own words more than adequately sum up the strength of character both women possessed when she wrote, "I had been pushed around all my life and felt at that moment I couldn't take it anymore." (Source)
Her actions won her attention from equal rights activists and she gave speeches and worked tirelessly toward ending discrimination for the rest of her life.
Like Frederick Douglass, John Brown was a bit more violent in support of abolition than Sojourner Truth would have approved of. (And by "a bit" we mean "way, way more.")
The white John Brown, of the infamous Harper's Ferry incident, was fervently anti-slavery. (Good man, John.) Born in the free state of Ohio, Brown moved to Kansas…where his first act, was to murder a handful of pro-slavery settlers. (Oh. Not such a good man, John.)
Brown claimed God supported his actions. We think Sojourner might have had a bit of an issue with that one.
His final speech at his trial for treason, where he claimed to have never intended to murder or incite rebellion but also showed no remorse, sparked support in the North and martyred him for the abolitionist cause.
On the other side of the fence, we have James Henry Hammond, devoted slavery proponent, and his Mudsill Speech.
This terrifying speech of pseudo-philosophy and pseudo-psychology flatly stated that society can only function if there is a lower class (read: slaves) for the upper class (read: white people) to build upon for progress.
Somehow, the slave class was considered "willing" to have their backs broken for the sake of making cotton barons rich, and any claims for racial equality should be considered abnormal and anarchic. Yeah, apparently Sojourner Truth and her points in "Ain't I a Woman?" were dangerously radical and needed to be kept down.
The scariest thing is that he wasn't the only one pontificating on the ethical application of slavery.