Mat 12:22-37 KJV
(22) Then was brought unto him one possessed with a devil, blind, and dumb: and he healed him, insomuch that the blind and dumb both spake and saw.
(23) And all the people were amazed, and said, Is not this the son of David?
(24) But when the Pharisees heard it, they said,
This fellow doth not cast out devils, but by Beelzebub the prince of the devils.
(25) And Jesus knew their thoughts, and said unto them,
Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand:
(26) And if Satan cast out Satan, he is divided against himself; how shall then his kingdom stand?
(27) And if I by Beelzebub cast out devils, by whom do your children cast them out? therefore they shall be your judges.
(28) But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you.
(29) Or else how can one enter into a strong man's house, and spoil his goods, except he first bind the strong man? and then he will spoil his house.
(30) He that is not with me is against me; and he that gathereth not with me scattereth abroad.
(31) Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.
(32) And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.
(33) Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit.
(34) O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
(35) A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.
(36) But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment.
(37) For by thy words thou shalt be justified, and by thy words thou shalt be condemned.
there is much debate and no true agreement in the body of Christ as to what exactly 'speaking against the Holy Spirit' is; looking at these scripture alone, it simply isn't clear.
Rev 13:4-6 KJV
(4) And they worshipped the dragon which gave power unto the beast: and they worshipped the beast, saying, Who is like unto the beast? who is able to make war with him?
(5) And there was given unto him a mouth speaking great things and blasphemies; and power was given unto him to continue forty and two months.
(6)
And he opened his mouth in blasphemy against God, to blaspheme his name, and his tabernacle, and them that dwell in heaven.
these verses are referring to the devil; this is not a 'slip of the tongue' in a weak moment; it is a certain and eternally final hatred for God and His 'tabernacle' (you and i and all believers still in flesh bodies), and all of His angels and people who have gone to be with Him already. you wouldn't be here asking about blasphemy if you held a certain and eternally final hatred of God, so you haven't blasphemed the Holy Ghost even if you said or do say some bad things about Him.
focus on God's words, they will push out the bad thoughts as you fill your mind with His words of goodness. if you simply reject the bad thoughts without replacing them with the good thoughts of the Good God who loves you, your focus will be on the bad thoughts even though you resist them.
your mind is like the gas tank on a car with no working gas gauge; if you want to fill up such a car with gas, all you have to do is keeping pumping in the gas until it gushes back out of the mouth of the tank to know it's full; pump God's words in your eyes and ears until His words come out of your mouth when blasphemous thoughts try to enter your mind; and you'll be so full of God that the devil's suggestions won't affect you. the thief does come, but he won't be able to get in if your mind is full of God