Walter Marshall was born in 1628 at Bishops Wearmouth in Durham, England. At age eleven, he went to study at Winchester College. He then became a fellow at New College, Oxford, from 1648 to 1657. He graduated with a Bachelor of Arts degree in 1652. Two years later, he was approved for the living of Fawley, Hampshire. In 1656, he was appointed to the vicarage of Hursley, Hampshire, four miles from Winchester. From 1657 to 1661, he served as a fellow at Winchester College. He married and had two daughters.
When the Act of Uniformity passed in 1662, ministers of the Church of England were asked to give proof of Episcopal ordination and their conformity to the Book of Common Prayer. Like hundreds of his Puritan colleagues, Marshall decided on the basis of conscience not to conform. He and other Nonconformists were ejected from their parishes on St. Bartholomew’s Day, August 24, 1662. In the preface to Marshall’s work on sanctification, a friend said, “He [Marshall] was put under the Bartholomew Bushel with near two thousand more lights whose illumination made the land a Goshen.”
Soon after that, Marshall was installed as minister of an Independent congregation at Gosport, Hampshire, where he served the last eighteen years of his life. At Gosport, he wrote a book on sanctification, titling it Gospel Mystery from Paul’s statement in 1 Timothy 3:16: “Great is the mystery of godliness.”