From a Smithsonian Magazine article, regarding the Burlington Quaker Meeting incident:
He finally rose to address this gathering of “weighty Quakers.” Many Friends in Pennsylvania and New Jersey had grown rich on Atlantic commerce, and many bought human property. To them Lay announced in a booming voice that God Almighty respects all peoples equally, rich and poor, men and women, white and black alike. He said that slave keeping was the greatest sin in the world and asked, How can a people who profess the golden rule keep slaves? He then threw off his great coat, revealing the military garb, the book and the blade.
A murmur filled the hall as the prophet thundered his judgment: “Thus shall God shed the blood of those persons who enslave their fellow creatures.” He pulled out the sword, raised the book above his head, and plunged the sword through it. People gasped as the red liquid gushed down his arm; women swooned. To the shock of all, he spattered “blood” on the slave keepers. He prophesied a dark, violent future: Quakers who failed to heed the prophet’s call must expect physical, moral and spiritual death.
The room exploded into chaos, but Lay stood quiet and still, “like a statue,” a witness remarked. Several Quakers quickly surrounded the armed soldier of God and carried him from the building. He did not resist. He had made his point.
The article also describes Lay throwing tobacco pipes at fellow Quakers at a meeting in Philadelphia, while loudly protesting the slave labor upon which tobacco growing relied. At other Quaker meetings, whenever anyone who owned slaves stood up to talk (which is how Quaker meetings work), he’d jump up and yell things like “There’s another n****-master!” to shame them. He regularly said slaveowners bore “the mark of the Beast” and were basically Satan incarnate.
It came as no surprise, to Lay or anyone else, that ministers and elders had him removed from one gathering after another. Indeed they appointed a “constabulary” to keep him out of meetings all around Philadelphia, and even that wasn’t enough. After he was tossed into the street one rainy day, he returned to the main door of the meetinghouse and lay down in the mud, requiring every person leaving the meeting to step over his body.
Lay was disowned by the Quakers’ Society in 1738 because he just wouldn’t stop calling out elders and rich members for their hypocrisy on the issue of slavery.
Also that year, Benjamin Franklin published one of Lay’s anti-slavery pamphlets, “All Slave-Keepers That Keep the Innocent in Bondage, Apostates.” But Franklin owned a slave and later bought two more. Lay called his ass out.
Lay refused to eat or wear anything produced in any way from slavery, and was a vegetarian. After his wife died he lived in a cave, kept goats and bees, farmed vegetables and fruit trees, and grew flax so he could spin it to make his own clothes. He had a library of 200 books in there.
Oh PS and he was barely over four feet tall and was disabled (kyphosis). He called himself “Little Benjamin” and likened himself to David going up against Goliath.