“The chief point on which it turns is to confirm Timothy, both in the faith of the gospel, and in the pure and constant preaching of it. But yet these exhortations derive no small weight from the consideration of the time when he wrote them. Paul had before his eyes the death which he was prepared to endure for the testimony of the gospel.
All that we read here, therefore, concerning the kingdom of Christ, the hope of eternal life, the Christian warfare, confidence in confessing Christ, and the certainty of doctrine, ought to be viewed by us as written not with ink but with Paul’s own blood; for nothing is asserted by him for which he does not offer the pledge of his death; and therefore this Epistle may be regarded as a solemn subscription and ratification of Paul’s doctrine.”
–John Calvin, Commentaries on the Epistles to Timothy, Titus, and Philemon, trans. William Pringle (repr. Grand Rapids: Baker, 1979), 179.