Matthew Poole's Commentary on Matthew 12:32
1. It cannot be any sin that is committed ignorantly. Paul was a blasphemer, but forgiven, because he did it ignorantly.
2. It must be a sin knowingly committed against the operations of the Holy Ghost. So was this sin of the Pharisees.
3. Apostasy must be an ingredient in it: If they fall away, saith the apostle, Hebrews 6:6. It is a sinning wilfully after the receiving the knowledge of the truth, Hebrews 10:26.
4. It should seem by this text persecution is an ingredient in it: the Pharisees did not only say this, but they spake it out of malice, designing to destroy Christ.
5. Most certainly it is, that though impenitency cannot be called that sin, yet it must be an ingredient in it, for what sins we truly repent of shall be forgiven, 1Jo 1:9; and therefore the apostle saith of such sinners, It is impossible they should be renewed by repentance.