He initially joined Henllan Amgoed chapel before going to William Evans in Carmarthen to become a minister.
In 1713, Mathias was briefly minister at Olney, before succeeding Richard Davis in Rothwell.
In 1726, Maurice wrote Byr a chywir Hanes Eglwys Rhydyceished yn eu Nheulltuad o Henllan, trwy y Blynyddoedd 1707, 1708, 1709, a short pamphlet on the history of Rhydyceished church, printed in 1727 in Maurice's book Y Wir Eglwys ('the true church').
This was answered by Jeremy Owen's pamphlet Golwg ar y Beiau (1732).
Other writings by Mathias Maurice include Social Religion Exemplify'd (1759),[1] Monuments of Mercy (1729) and A modern question affirmed and approved (1739).