Jones corresponded with Thomas Charles (q.v.) about the foundation of Sunday schools, and himself founded one at Creaton in 1789. He also persuaded the S.P.C.K. to publish in 1799 an edition of ten thousand copies of the Bible in Welsh; when the demand for Welsh Bibles persisted, he sought to persuade the Society to issue a further edition, but failed. Later, as a result of his efforts and those of Thomas Charles and others, the British and Foreign Bible Society was established.

Jones was a fervent Evangelical preacher and a prolific writer. He was the author of seven works in Welsh, mainly translations (including one of Baxter's Saints’ Everlasting Rest) and seventeen in English, the last being published in 1841. Perhaps his best-known work is The Welsh Looking-glass, 1812 [a remonstrance against the secession of the Welsh Calvinistic Methodists from the Established Church].