You know, many folks consider Mathew Henry a Calvinist according to his commentaries. Whether or not he was I wouldn't say, I haven't read all he has written, however, I doubt he believed a justified believer could then become unjustified......
From Matthew Henry himself.....
IV. Whom he justified those he also glorified. The power of corruption being broken in effectual calling, and the guilt of sin removed in justification, all that which hinders is taken out of the way, and nothing can come between that soul and glory. Observe, It is spoken of as a thing done: He glorified, because of the certainty of it; he hath saved us, and called us with a holy calling. In the eternal glorification of all the elect, God's design of love has its full accomplishment. This was what he aimed at all along - to bring them to heaven. Nothing less than that glory would make up the fulness of his covenant relation to them as God; and therefore, in all he does for them, and in them, he has this in his eye. Are they chosen? It is to salvation. Called? It is to his kingdom and glory. Begotten again? It is to an inheritance incorruptible. Afflicted: It is to work for them this exceeding and eternal weight of glory. Observe, The author of all these is the same. It is God himself that predestinated, calleth, justifieth, glorifieth; so the Lord alone did lead him, and there was no strange God with him. Created wills are so very fickle, and created powers so very feeble, that, if any of these did depend upon the creature, the whole would shake. But God himself hath undertaken the doing of it from first to last, that we might abide in a constant dependence upon him and subjection to him, and ascribe all the praise to him - that every crown may be cast before the throne. This is a mighty encouragement to our faith and hope; for, as for God, his way, his work, is perfect. He that hath laid the foundation will build upon it, and the top-stone will at length be brought forth with shoutings, and it will be our eternal work to cry, Grace, grace to it. (Comments on Romans 8:30)
Thirdly, He has undertaken for their security and preservation to this happiness.
a. They shall be saved from everlasting perdition. They shall by no means perish for ever; so the words are. As there is an eternal life, so there is an eternal destruction; the soul not annihilated, but ruined; its being continued, but its comfort and happiness irrecoverably lost. All believers are saved from this; whatever cross they may come under, they shall not come into condemnation. A man is never undone till he is in hell, and they shall not go down to that. Shepherds that have large flocks often lose some of the sheep and suffer them to perish; but Christ has engaged that none of his sheep shall perish, not one.
b. They cannot be kept from their everlasting happiness; it is in reserve, but he that gives it to them will preserve them to it. (a.) His own power is engaged for them: Neither shall any man pluck them out of my hand. A mighty contest is here supposed about these sheep. The Shepherd is so careful of their welfare that he has them not only within his fold, and under his eye, but in his hand, interested in his special love and taken under his special protection (all his saints are in thy hand, Deu_33:3); yet their enemies are so daring that they attempt to pluck them out of his hand - his whose own they are, whose care they are; but they cannot, they shall not, do it. Note, Those are safe who are in the hands of the Lord Jesus. The saints are preserved in Christ Jesus: and their salvation is not in their own keeping, but in the keeping of a Mediator. The Pharisees and rulers did all they could to frighten the disciples of Christ from following him, reproving and threatening them, but Christ saith that they shall not prevail. (b.) His Father's power is likewise engaged for their preservation, Joh_10:29. He now appeared in weakness, and, lest his security should therefore be thought insufficient, he brings in his Father as a further security. Observe, [a.] The power of the Father: My Father is greater than all; greater than all the other friends of the church, all the other shepherds, magistrates or ministers, and able to do that for them which they cannot do. Those shepherds slumber and sleep, and it will be easy to pluck the sheep out of their hands; but he keeps his flock day and night. He is greater than all the enemies of the church, all the opposition given to her interests, and able to secure his own against all their insults; he is greater than all the combined force of hell and earth. He is greater in wisdom than the old serpent, though noted for subtlety; greater in strength than the great red dragon, though his name be legion, and his title principalities and powers. The devil and his angels have had many a push, many a pluck for the mastery, but have never yet prevailed, Rev_12:7, Rev_12:8. The Lord on high is mightier. [b.] The interest of the Father in the sheep, for the sake of which this power is engaged for them: “It is my Father that gave them to me, and he is concerned in honour to uphold his gift.” They were given to the Son as a trust to be managed by him, and therefore God will still look after them. All the divine power is engaged for the accomplishment of all the divine counsels. [c.] The safety of the saints inferred from these two. If this be so, then none (neither man nor devil) is able to pluck them out of the Father's hand, not able to deprive them of the grace they have, nor to hinder them from the glory that is designed them; not able to put them out of God's protection, nor get them into their own power. Christ had himself experienced the power of his Father upholding and strengthening him, and therefore puts all his followers into his hand too. He that secured the glory of the Redeemer will secure the glory of the redeemed. Further to corroborate the security, that the sheep of Christ may have strong consolation, he asserts the union of these two undertakers: “I and my Father are one, and have jointly and severally undertaken for the protection of the saints and their perfection.” This denotes more than the harmony, and consent, and good understanding, that were between the Father and the Son in the work of man's redemption. Every good man is so far one with God as to concur with him; therefore it must be meant of the oneness of the nature of Father and Son, that they are the same in substance, and equal in power and glory. The fathers urged this both against the Sabellians, to prove the distinction and plurality of the persons, that the Father and the Son are two, and against the Arians, to prove the unity of the nature, that these two are one. If we should altogether hold our peace concerning this sense of the words, even the stones which the Jews took up to cast at him would speak it out, for the Jews understood him as hereby making himself God (Joh_10:33) and he did not deny it. He proves that none could pluck them out of his hand because they could not pluck them out of the Father's hand, which had not been a conclusive argument if the Son had not had the same almighty power with the Father, and consequently been one with him in essence and operation. (Comments on John 10:28)
