Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.

People's New Testament

12:31 The blasphemy against the Holy Ghost shall not be forgiven. Compare Mr 3:28 Lu 12:10. Much discussion has arisen concerning the nature of sin against the Holy Spirit, and nothing is plainer. Mr 3:30 explains it. It was ascribing Christ's works to demoniac influence. These works were wrought by the power of the Spirit.

Wesley's Notes

12:31 The blasphemy against the Spirit - How much stir has been made about this? How many sermons, yea, volumes, have been written concerning it? And yet there is nothing plainer in all the Bible. It is neither more nor less than the ascribing those miracles to the power of the devil, which Christ wrought by the power of the Holy Ghost. Mark 3:28; Luke 12:10.

Scofield Reference Notes

Margin sin

Sin. See Scofield Note: "Rom 3:23".

Margin blasphemy

Ascribing to Satan the work of the Holy Spirit. Cf. Mt 12:24,32,40.

Jamieson-Fausset-Brown Bible Commentary

31. Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men-The word "blasphemy" properly signifies "detraction," or "slander." In the New Testament it is applied, as it is here, to vituperation directed against God as well as against men; and in this sense it is to be understood as an aggravated form of sin. Well, says our Lord, all sin-whether in its ordinary or its more aggravated forms-shall find forgiveness with God. Accordingly, in Mark (Mr 3:28) the language is still stronger: "All sin shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme." There is no sin whatever, it seems, of which it may be said, "That is not a pardonable sin." This glorious assurance is not to be limited by what follows; but, on the contrary, what follows is to be explained by this.

but the blasphemy against the Holy Ghost shall not be forgiven unto men.

Matthew Henry's Concise Commentary

12:31,32 Here is a gracious assurance of the pardon of all sin upon gospel terms. Christ herein has set an example to the sons of men, to be ready to forgive words spoken against them. But humble and conscientious believers, at times are tempted to think they have committed the unpardonable sin, while those who have come the nearest to it, seldom have any fear about it. We may be sure that those who indeed repent and believe the gospel, have not committed this sin, or any other of the same kind; for repentance and faith are the special gifts of God, which he would not bestow on any man, if he were determined never to pardon him; and those who fear they have committed this sin, give a good sign that they have not. The trembling, contrite sinner, has the witness in himself that this is not his case.