Lay was born in Colchester, England, to Quaker parents William Lay and Mary Dennis. After a basic education he was apprenticed to a glove maker. Later he worked on his brother’s farm before going to sea at the age of about twenty. He was a man of small stature being about 4 foot 7 inches tall and he also had a hunch back. After returning home he married and went to live in London. Lay lived the life of a hermit, was a committed vegetarian, did not drink tea or coffee, or wear anything made from leather and preferred to make his own clothes. Throughout his life he was given to eccentric behaviour and committed acts that startled others. His fellow Quakers were annoyed by his vociferous opposition to the practice of allowing ministers to speak when they had not been directly prompted by God. Devonshire House monthly meeting disowned him in 1720. He then moved to Colchester where he continued to disrupt Quaker meetings and was given what amounted to a second disownment.
In 1731 he went to Barbados where he was appalled to see the conditions under which slaves were kept. He took up their cause and soon started to berate Quaker slaveholders. He went to live near Philadelphia and continued his protests against slave owning. Lay wrote a tract about the evils of slavery entitled ‘All Slave-Keepers the Keep the Innocent in Bondage, Apostates’. His friend Benjamin Franklin had this published in 1737. In this publication he made many accusations against individual Friends and the Society as a whole.
Quaker institutions were angered by what he had written, and, more seriously, by the fact that the book had been published as a Quaker document without Quaker approval. The 'Overseers of the Press' were supposed to authorise all publications that put forward Quaker views. To publicly voice an opinion and present it as evolving from Quaker principles, without such approval, was a serious matter at that time. Philadelphia Yearly Meeting took out advertisements in various newspapers to distance themselves from Lay’s views. This disapproval did not deter him and whenever the occasion arose he would speak out against slavery.
One of his most memorable exploits took place in Burlington, New Jersey in 1738. After entering the Meeting House he removed his outer clothing to reveal a military uniform including a sword. After a lengthy tirade he thrust the sword into a bladder of red liquid that he had hidden between the covers of a Bible, spattering the Quakers sitting nearby. He told them that owning slaves was akin to stabbing a man to death and that the red liquid was a symbol of the blood of slaves on Quaker slave owner’s hands. This outburst caused him to be disowned once more. Lay’s tactics were in contrast to other abolitionists such as John Woolman, who was always careful not to publicly criticise Friends or to cause offence. Woolman’s writings all went through the accepted Quaker approval channels.
Lay continued to consider himself a Quaker throughout his life despite being disowned by the Society. He also continued to make dramatic gestures. He stood outside a meeting house in the snow without a coat and in bare feet to remind Friends of the hardship experienced by slaves. On another occasion he kidnapped a child and only returned him to his father when the authorities came to his dwelling place. He said that this was an attempt to make people realise how African parents felt when their children were captured and sold into slavery.
Although Lay is usually remembered for his influential role in persuading the Society of Friends to renounce slavery, he was also ahead of his time in supporting other causes that he supported such as temperance. Criminal reform also interested him and he produced a pamphlet that advocated the abolition of capital punishment.
In 1758 Philadelphia Monthly Meeting decided that slave holders should be excluded from all business meetings. It is said that when this news reached Lay he rose from his chair and exclaimed “I can now die in peace”. He died in the following year and is buried in the Quaker burial ground in Abington, near Philadelphia.