William Gadsby (1773-1844) was baptised in 1793. God marked him out for the ministry early on, and in 1805 he was called to Manchester, where he pastored the Particular Baptist church (later at Rochdale Road) until his death. In this booklet Gadsby analyses and remarks upon a letter written by 'Gaius' (evidently a pen name for Andrew Fuller), which appeared in the Evangelical Magazine for December 1804. The letter gives reasons for believing the moral law as the rule of conduct for believers, and Gadsby's article refutes them. To it are added his letters on the same subject to Mr Upton, and part of his children's catechism.