Renwick returned from Holland in the autumn of 1683.  Escaping some dangers at sea, he visited Dublin, where he bore a faithful testimony against the silence of ministers in the public cause, and left behind him a favourable impression on the minds of some of his Christian zeal and devotedness.  In September, 1683, he landed in Scotland, and on the 3d of November, he entered on his arduous work of preaching the Gospel in the fields, and lifting up the standard of a covenanted testimony.  He preached on that day at Darmead in the parish of Cambusnethan.  From that time, till he closed his glorious career and won the martyr’s crown, he preached with eminent fidelity and great power the glorious gospel of the grace of God.  His public labours were continued for a period of nearly five years, and extended to many districts in the east, south, and west of Scotland.  In remote glens, unfrequented moorlands, often in the night season, and amid storm and tempest, when the men of blood could not venture out of their lairs, to pursue the work of destruction, he displayed a standard for truth, and eagerly laboured to win souls to Christ.  His last sermon was preached at Borrowstoness, from Isaiah liii. 1, on January 29th, 1688.

Though he ever testified boldly against the defections of the times, especially the Indulgence, and insisted on disowning the papist James, as not being a constitutional monarch, and on maintaining fully Presbyterian order and discipline, and all the covenanted attainments, his discourses were eminently evangelical.  His darling themes were salvation through Christ, and the great matters of practical godliness.  With wonderful enlargement and attractive sweetness, he unfolded the covenant of grace—­the matchless person and love of Christ—­the finished atonement, and its sufficiency for advancing the glory of the Godhead, and for the complete salvation of elect sinners.  Considering Renwick’s youth, being but nineteen years of age when he entered on his great work, he was endowed with singular qualifications as a preacher of the gospel.  These remarkably fitted him for the great work to which he was called—­promoting the Redeemer’s glory, in awakening and converting sinners, and in edifying and comforting the Church in a season of suffering and trial.  He was, moreover, gifted with personal talents, natural and acquired, that rendered him an attractive and powerful preacher of the gospel.  His aspect was solemn and engaging.  His personal appearance, even when harassed by incessant labours and privations, night wanderings and hair-breadth escapes from enemies, was sweet and prepossessing.  His manner in preaching was lucid and affecting.  His whole heart was thrown into his discourses.  He often rose to the height of the most moving eloquence; and with the constant reality of God’s presence and love, and the dread realities of persecution, and violent death, and eternity, before him, he poured out his soul in such strains of heavenly enlargement, that his hearers were melted, subdued, and raised above the fear of death, and the terror of enemies.