10 His will indeed was to exercise us by the difficulty of the question, not to deceive us by a false decision. Wherefore there is no necessity for any one to think, that every blasphemy or every word which is spoken against the Holy Ghost has no remission; but necessary it plainly is, that there should be some certain blasphemy, and some word which if it be spoken against the Holy Ghost can never attain to pardon and forgiveness. For if we take it to mean “every word,” who then can be saved?
But if again we think there is no such “word,” we contradict the Saviour. There is then without doubt some certain blasphemy and some word which if it be spoken against the Holy Ghost, shall not be forgiven. Now what this word is, it is the Lord's will we should enquire; and therefore He has not expressed it. His will, I say, was that it should be enquired into, not denied. For the style of the Scriptures is often such, that when anything is so expressed as not to be limited either to a universal or particular signification, it is not necessary that it should be understood universally, and not particularly.
This proposition then would be expressed in its whole extent, that is, universally, if it were said, “All blasphemy of the Spirit shall not be forgiven;” or, “Whosoever speaks any word whatsoever against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.” But it would be expressed partially, that is, particularly, if it were said, “Some certain blasphemy of the Spirit shall not be forgiven.” But because this proposition is laid down neither in a universal, nor a particular form (for it is not said, “Every blasphemy;” or some certain blasphemy of the Spirit; but only indefinitely, “blasphemy of the Spirit shall not be forgiven;” neither is it said, “Whosoever speaks any word whatever,” or “whosoever speaks some certain word,” but indefinitely, “whosoever speaks a word”), there is no necessity that we should understand “every blasphemy and every word;” but necessary it plainly is that the Lord designed some kind of blasphemy, and some word to be understood; though He would not express it, that, if we should receive any right understanding of it by asking, and seeking, and knocking, we might not entertain a low esteem of it.
Source: Sermons on Selected Lessons of the New Testament (New Advent)