Today's Gospel (Mark 3:22-30) contains the infamous saying about the "unforgivable sin" - blaspheming against the Holy Spirit. It is probably one of the most difficult texts in Scripture to understand. Merriam-Webster defines blasphemy as: A. the act of insulting or showing contempt or lack of reverence for God; the act of claiming the attributes of deity.
From the passage and the interchange between Jesus and the scribes, it would seem that the second part of that definition is what applies here. When the scribes tried to attribute to "Beelzebul" the power to expel demons, they were ascribing Satan a power that belongs only to God. So, when Jesus condemns those who blaspheme against the Holy Spirit, it would apply to anyone who tries to ascribe the Spirit's power to another.
This really goes back to the first of the commandments handed on to Moses: "You shall not have other gods besides me" (Exodus 20:3).
This powerful warning of the Lord means we have to be on guard against this sin of blaspheming against the Holy Spirit in our own lives. The temptation is always present, since Satan knows how susceptible we are to the lure of power. How many times have I thought "If I was God for just a few minutes, I would straighten things out." As if I could do a better job that God! How preposterous! This kind of thinking can lead us to conclude that God must not be doing such a good job, if things are such a mess. It is then a short leap to thinking that God must not really be present. From there it is a short trip to abandoning belief in God's very existence. Once that occurs, Satan has won.
A very subtle but effective method that Satan employs. Gradual, but insistent. That is also why the Lord was so strong in His warning. No one sets out to "blaspheme against the Holy Spirit." But the insidious temptations of the devil can still lead us to that destination if we are not careful.
Better to let God be God, and do our best to follow His will, even when we do not understand it completely, or at all! After all, no one ever lost eternal happiness in heaven by doing what God wanted. But those who blaspheme against the Holy Spirit...???