Mark 3:26-30

Mark 3:26 (KJB)
And if Satan rise up against himself, and be divided, he cannot stand, but hath an end.

Then Jesus applies that principle to the kingdom of Satan. If Satan divides himself, then how could he have one unified kingdom? It would weaken and implode and thus destroy itself. Therefore, if Satan is to have a strong united front, then all the devils in his kingdom must be united in both cause and desire to overthrow the Kingdom of God.

Mark 3:27 (KJB)
No man can enter into a strong man's house, and spoil his goods, except he will first bind the strong man; and then he will spoil his house.

Jesus then tells another parable. He likens Satan to the strong man and those who are devil possessed as his goods. This would also refer to the unsaved who are the goods of Satan. Those who are devil possessed have no will of their own as we saw in the Gadarene Demoniac. The only way that one can affect the change in a person’s life is that the strong man must first be bound. This means that a stronger man than he is required to do the job. Once the strong man is bound, then his house will be able to be spoiled without any intervention on his part. This happened at the cross where Satan was bound and could no longer stop a person from being saved or hinder prayers like he did to Daniel. (Rev 20:2 KJV) And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years, The thousand years is symbolic of the entire New Testament as Satan is bound for the entire duration, until such a time that he is released right before the return of the Lord Jesus Christ. Jesus is telling these Pharisees that He is stronger than Satan and therefore His power is of God.

Mark 3:28 (KJB)
Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme:

Jesus uses the word “verily” to begin this statement and it means “truly” because a serious truth is about to follow.” He is stating that all kinds of blasphemy and sin are forgivable sins and those who are the Elect of God will have those sins forgiven because in all of our lives, we have committed heinous sins of blasphemy. From telling evil jokes to just plain cursing and swearing the name of God and Jesus. Jesus now halts from using parables and goes into a straightforward warning.

Mark 3:29 (KJB)
But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation:

Then Jesus states in no uncertain terms that blasphemy against the Holy Ghost will never be forgiven. What the Pharisees and Scribes had just done was to proclaim that the miracles that Jesus did such as delivering someone from the power of Satan was done by the power of Satan. The miracles of Jesus were done under the power of the Holy Spirit and the Holy Spirit is the third person of the God head, fully God. What they were saying was that the miracles Jesus did was under the power of Satan, thus stating that the Holy Spirit was an unclean Spirit akin to Satan himself. This would mean that they were also saying that if the Holy Spirit was an unclean Spirit, that would make God the Father an unclean Spirit since the Holy Spirit was eternal God Himself. This was blasphemy of the highest order and was a sin that was not forgiven.

Mark 3:30 (KJB)
Because they said, He hath an unclean spirit.

Jesus had made such definite statements in the previous two verses because they were continually accusing Him of having an unclean spirit. The imperfect tense in the Greek underlying “because they said” tells us that they had continually accused Him of being under the authority of Satan and was not just a one time accusation. They accused Him of having an unclean spirit which means they were teaching the Holy Spirit was under the authority of Satan. These people hated Jesus so much that they did not realize the immensity of the accusations they were making and it cost them eternity because they could not be redeemed from this one sin.