The Christian must every day take care of what is going to come out of his mouth, because there are words that can hurt. This is why we can hear a saying that says “think before you speak”.
A good man brings good things out of the good stored up in him, and an evil man brings evil things out of the evil stored up in him.
When Jesus left the place, a large crowd followed Him, they wanted to hear the message of the Master, who taught all these people that all blasphemy that man committed against the son of man can be forgiven, but that there is something that has no forgiveness, and it is blasphemy with the Holy Spirit.
It is for this reason we must take into account everything we are going to say, because as Jesus explained, that when man lied, blasphemed, criticized, this could be forgiven. But to speak evil of the Holy Spirit is a sin that is not forgiven.