William Law (1686 – 9 April 1761) was a Church of England priest who lost his position at Emmanuel College, Cambridge, when his conscience would not allow him to take the required oath of allegiance to the first Hanoverian monarch, King George I.

His personal integrity, as well as his mystic and theological writing, greatly influenced the evangelistic movement of his day, as well as Enlightenment thinkers such as the writer Samuel Johnson and the historian Edward Gibbon.

His pupil then went abroad but Law was left at Putney, where he remained in Gibbon's house for more than 10 years, acting as a religious guide not only to the family but to a number of earnest-minded people who came to consult him.

There, he was joined by Elizabeth Hutcheson, the rich widow of his old friend (who recommended on his death-bed that she place herself under Law's spiritual guidance), and Hester Gibbon, sister to his late pupil.

Law's Case of Reason (1732), in answer to Tindal's Christianity as old as the Creation, is to some extent an anticipation of Joseph Butler's argument in the Analogy of Religion.

[2] A Serious Call to a Devout and Holy Life (1729), together with its predecessor, A Practical Treatise Upon Christian Perfection (1726), deeply influenced the chief actors in the great evangelistic revival.

Samuel Johnson,[4] Gibbon, Lord Lyttelton and Bishop Home all spoke enthusiastically of its merits; and it is still the work by which its author is popularly known.

The devotional writer Andrew Murray was so impressed by Law's writings that he republished a number of his works, stating "I do not know where to find anywhere else the same clear and powerful statement of the truth which the Church needs at the present day.

The journal of John Byrom mentions that, probably around 1735 or 1736, the physician and Behmenist George Cheyne had drawn Law's attention to the book Fides et Ratio, written in 1708 by the French Protestant theologian Pierre Poiret.

[6][7] From then on, Law's writings, such as A Demonstration of the Errors of a late Book (1737) and The Grounds and Reasons of Christian Regeneration (1739), contained a mystical note.

John Byrom wrote a poem based on An Earnest and Serious Answer, which was found among the manuscripts of Samuel Richardson after his death in 1761.

I do not mean by misrepresenting his sentiments; (though some of his profound admirers are positive that you misunderstand and murder him throughout) but by dragging him out of his awful obscurity; by pouring light upon his venerable darkness.

Men may admire the deepness of the well, and the excellence of the water it contains: But if some officious person puts a light into it, it will appear to be both very shallow and very dirty.

Law had found some illustrations made by the German early Böhme exegetist Dionysius Andreas Freher (1649–1728), which had been included in this edition.