Blasphemy against the Holy Spirit is the denial by the witness of his life that an individual was forgiven, received God's Holy Spirit, and then failed to live by faith, returning to a life of sin.
Spiritually, He says to us: "See, I've called you out of this evil world and healed you. You must now stop sinning—repent of your wicked ways—lest you return to the world and end up worse than when you started!"