1 John 5:6 - Joseph Benson’s Commentary on the Old and New Testaments

This is he that came by water and blood Here the apostle evidently alludes to the testimony borne by him in his gospel, that when the soldier pierced Christ's side, forthwith there came out blood and water; a fact which the apostle represents as of great importance; adding, He that saw it bare record, and his record is true: and he knoweth that he saith true, that ye might believe. It was important, not only, 1st, As being a full proof, in opposition to the doctrine of the Docetæ, that Christ came in the flesh, and really died; of which see on John 19:34: but, 2d, Because it was emblematical of the offices which he sustained, and of the salvation he hath procured for his people. For the water was a symbol of the purity of his doctrine, instructing men in the purest morals, and of his own pure and holy example; and, what is of still greater importance, of the purifying grace of which he is the fountain, sanctifying and cleansing such as believe in him, from all filthiness of flesh and spirit: while the blood which issued from him was an emblem both of the sufferings which awaited his followers, who were to seal the truth with their blood, and of his own sufferings, whereby he hath made atonement for the sins of the world, and procured for his followers a free and full justification. Thus, as an eminent divine observes, he also manifested himself to be the Son of God, the promised Messiah, by fulfilling those types and ceremonies of the law which were performed by water and blood: the former whereof, denoting purification from sin, he fulfilled by cleansing us by his Spirit, (signified by water, John 7:38-39,) from the corruption of nature, and the power and pollution of sin, and so restoring the image of God in us, Ezekiel 36:25; Ezekiel 36:27; Ephesians 5:25-26; Titus 2:14; Titus 3:5. The latter, which prefigured the expiation of our sin, he fulfilled by shedding his blood to atone for our sins, and to procure for us deliverance from the guilt and punishment of them, (Romans 5:9; Galatians 3:13; Ephesians 1:7,) and to restore us to the favour of God again. Not by water only Not only was his doctrine pure, and his life holy, and not only may purifying grace be derived from him, but he came by blood, shed for the expiation of our guilt, for these things must go together; because it will not avail us to be enabled to avoid sin, and to live in a holy manner for the time to come, except the sins of the time past be expiated. And it is the Spirit that beareth witness To these things, namely, in the writings of the ancient prophets, who have spoken largely concerning both, and in the discourses and writings of the apostles, who have borne a still more clear and full testimony to them; and also in the hearts of all the faithful, who, as they are fully convinced of their need of both pardon and holiness, so through the merits and Spirit of Christ they receive both.