These are very strong verses which leave no room for compromise. Jesus is clear that there is no middle way (somewhere between loving Jesus and hating him). It does not exist. Those who do not work with Jesus are working against Him and having an anti-Jesus effect on others, discouraging them from following Him. Those who will not identify with Jesus are against Him, they are his enemies. However they can turn and repent, and if they do they will be forgiven.
 
Forgiveness is available to everybody who admits that they are wrong, whatever the sin. But there is one exception: blasphemy against the Holy Spirit. What is that? A number of suggestions have been made; but the context of the verses will help our understanding. Jesus had just been accused of being demonised; they said He was under the authority of Satan.
 
But Jesus had come to defeat Satan, not collaborate with him. By refusing to see who Jesus was, they blasphemed against the Holy Spirit by saying that He was evil. Having clearly seen the Son of God acting with divine authority, their conclusion prevented them being included in the holy fellowship of the Spirit of God with the Son of God (John 17:20-23). Without accepting Jesus as Saviour, Lord and God there is no possibility of forgiveness (Acts 13:38).
 
We must be clear about who Jesus is. Our eternal destiny depends on that understanding. He cannot be reduced to being just a good teacher or an inspired prophet: He is God who lived within the constraints of a human body so that He could die for our sins. Refusal to accept His deity is to deny the essence of His nature; and without believing in Him and welcoming Him, nobody can be saved (Acts 4:12).