Law was a busy writer under three heads:--
1. _Controversy._--In this field he had no contemporary peer save perhaps Richard Bentley. The first of his controversial works was _Three Letters to the Bishop of Bangor_ (1717), which were considered by friend and foe alike as one of the most powerful contributions to the Bangorian controversy on the high church side. Thomas Sherlock declared that "Mr Law was a writer so considerable that he knew but one good reason why his lordship did not answer him." Law's next controversial work was _Remarks on Mandeville's Fable of the Bees_ (1723), in which he vindicates morality on the highest grounds; for pure style, caustic wit and lucid argument this work is remarkable; it was enthusiastically praised by John Sterling, and republished by F. D. Maurice. Law's _Case of Reason_ (1732), in answer to Tindal's _Christianity as old as the Creation_ is to a great extent an anticipation of Bishop Butler's famous argument in the _Analogy_. In this work Law shows himself at least the equal of the ablest champion of Deism. His _Letters to a Lady inclined to enter the Church of Rome_ are excellent specimens of the attitude of a high Anglican towards Romanism. His controversial writings have not received due recognition, partly because they were opposed to the drift of his times, partly because of his success in other fields.
2. _Practical Divinity._--The _Serious Call to a Devout and Holy Life_ (1728), together with its predecessor, _A Treatise of Christian Perfection_ (1726), deeply influenced the chief actors in the great Evangelical revival. The Wesleys, George Whitefield, Henry Venn, Thomas Scott and Thomas Adam all express their deep obligation to the author. The _Serious Call_ affected others quite as deeply. Samuel Johnson, Gibbon, Lord Lyttelton and Bishop Horne all spoke enthusiastically of its merits; and it is still the only work by which its author is popularly known. It has high merits of style, being lucid and pointed to a degree. In a tract entitled _The Absolute Unlawfulness of Stage Entertainments_ (1726) Law was tempted by the corruptions of the stage of the period to use unreasonable language, and incurred some effective criticism from John Dennis in _The Stage Defended_.