He was later deprived by the Privy Council, on 1 October 1662, for disobeying the Act of Parliament in not keeping a day of thanksgiving for His Majesty's Restoration, and not obtaining presentation and collation from the archbishop before 20 September.

Disregarding this sentence, he was charged to appear before the Council on 7 January 1669, and appointed to continue in his confinement, but on petition he was allowed to visit Edinburgh about law affairs.

In 1679 he joined Richard Cameron in founding the Cameronians (afterwards the Reformed Presbyterians), who embodied their principles in a Declaration at Sanquhar, on 22 June 1680, disowning the king's authority.

After numerous hair-breadth escapes he was apprehended at Covington Mill, Lanarkshire, during the night of 12 July 1681 by a party of dragoons led by James Irving of Bonshaw (who got the reward).

He married Margaret (died 12 Aug. 1656, within a year and a day of their marriage), daughter of Nicol Brown, burgess of Edinburgh, widow of Andrew Bethune of Blebo.

"[8] On 22 June 1680 Cargill's associate Richard Cameron issued the Sanquhar Declaration, calling for war against King Charles II and the exclusion of his brother, afterwards James VII, from the succession.

[5] Though Cargill's very stringent views were not generally accepted by his countrymen, both he and his friend Cameron took a great hold on the popular sympathy and regard.

Some sermons, lectures, and his last speech and testimony have been printed; but Peter Walker in the 'Remarkable Passages' in which he records his life in 'Biographia Presbyteriana,' indicates that the impression produced by them was far inferior to that of his spoken discourses.