He had resolved to join the Church of Rome when a commission of Lutheran divines pointed out flaws in his written argument and called his attention to the English Church as apparently possessing that apostolic succession and manifesting that fidelity to ancient institutions which he desired.
The learned labours to which the remainder of his life was devoted were rewarded with an Oxford degree (DD) and a royal pension.
In 1726 a monument by Francis Bird was erected to him by Edward Harley, Earl of Oxford, in Westminster Abbey.
Some account of Grabe's life is given in Robert Nelson's Life of George Bull, and by George Hickes in a discourse prefixed to the pamphlet against William Whiston's Collection of Testimonies against the True Deity of the Son and of the Holy Ghost.
[4] His works, which show him to have been learned and laborious but somewhat deficient in critical acumen, include a Spicilegium SS.