James Erskine, Lord Grange (1679-1754), was the son of Charles Erskine, Earl of Mar (in Scotland). Since his older brother John succeeded to their father's title, James trained for law. He was made a Lord of Justiciary in 1706, taking the title of Lord Grange, and raised to the bench the same year. In 1710 Erskine succeeded Adam Cockburn of Ormiston as Lord Justice Clerk. While sympathetic with the Jacobite cause, Erskine took no part in the 1715 Rebellion, which allowed him to stay in favour with Presbyterians in Scotland and active in the General Assembly. When Robert Walpole succeeded in excluding Scottish judges from sitting in the British House of Commons, Erskine resigned his judgeship and was elected an MP in 1734. He generally resided in London from then on, even after leaving Parliament in 1747.
Erskine was drawn into Methodist circles in London in the early 1740s by George Whitefield, who brought him to the attention of the Wesley brothers. He was soon offering legal advice to the Wesleys on Methodist matters. He was particularly helpful to Charles Wesley when the latter was falsely accused of inappropriate behaviour in late 1744. Charles returned this favour in 1750 by helping restore the relationship between Erskine and his daughter. This personal closeness was seasoned by some theological tension, as Erskine sided more naturally with the Calvinist wing of Methodism, particularly on the issues of election and Christian perfection.