Born in 1676, in the town of Duns, in the Border country of Scotland, Thomas Boston learned through his childhood experiences to sympathise with the Presbyterian cause. His father, John Boston, was a strong opponent of Prelacy; and for this Nonconformity, he suffered a period of imprisonment. Thomas spent at least one night in Duns jail with him "to keep him company." When James II, in 1687, gave liberty of worship to dissenters from the Established Church—which he did out of regard for his RC subjects, John Boston was not slow to avail himself of his new-found liberty. He used to wait on the ministry of Henry Erskine, the father of Ebenezer and Ralph Erskine, with whom Thomas Boston was to be so closely associated in after years in making a stand for the free offer of the Gospel. It was while attending one of these services that Thomas, then a boy of 11, was converted. He refers to the event in his Soliloquy on the Art of Man-fishing, which he published while still a young licentiate.
After graduating from the University of Edinburgh, he was licensed as a preacher of the gospel in 1697. But he was not ordained until 1699, when he became minister of the parish of Simprin. It was there that he first preached the sermons which were later published under the title of Human Nature in its Fourfold State. Simprin was a discouraging field of service, but under his zealous ministry it became, to quote his own description, "a field which the Lord has blessed."
In 1707, Boston was transferred to the parish of Ettrick, where he found the people sadly divided by separatism. The Cameronians, who repudiated the Revolution Settlement of 1688, stood aloof from his ministry, and, while among the parishioners generally there was much zeal for the church, there was but little vital godliness. Not until 1710, three years after his induction to Ettrick, did Boston dispense the sacrament of the Lord's Supper there; and, indeed, even after laboring for a further five years there, he concluded that all had been in vain. But when, in 1716, he received a call to Closeburn, his people at Ettrick showed the utmost anxiety at the prospect of losing their minister. But the transferral never took place. Boston stayed at Ettrick and witnessed a great work of grace in what had been a spiritual wilderness. It is noteworthy that whereas at his first dispensation of the Lord's Supper there, only some 60 persons communicated, at his last communion, in 1731, the number of participants was 777.
It was during his Ettrick ministry that his Fourfold State was first published, and by it his ministry was extended far and wide. But the doctrinal content of those discourses had been greatly influenced by his discovery, in a humble home in Simprin, of Edward Fisher's treatise The Marrow of Modern Divinity. This little book had the effect of giving Boston a fuller insight into the grace of God as the sole cause of salvation; and it immediately "gave a tincture," as he put it, to his preaching.
Boston was a man of scholarly attainments, a first-class Hebraist, and a theologian of such eminence that Jonathan Edwards judged him to have been "a truly great divine." Never a robust man, he had a full share of tribulation, as his Autobiography so touchingly shows. He left behind him 12 volumes of collected writings. The two books which did most to extend his ministry throughout Scotland, and even England and America, were The Crook in the lot and Human Nature in its Fourfold State.