Here it is ...
Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come. [Matthew 12 : 32 NIV]Firstly, let's make the obvious comment.
There is no unpardonable or unforgivable sin. How can there be?
Regardless of what this verse might or might not say, Jesus died on the cross and paid the penalty for all our sins, as we have been assured many times through the Bible. For example 1 John 2:2; 2 Corinthians 5:19.
Secondly, by looking at our verse here, we can see that this is also true.
All sin against Jesus will be forgiven - a statement of assurance.
Sin against the Holy Spirit will not be forgiven in this age (the age in which Jesus lived and spoke these words) or in the age to come (the church age in which we are currently living).
However, the age after that, which includes the judgement pictured by the Great White Throne and the purification and cleansing pictured by the Lake of Fire, will surely look after this sin.
Whatever speaking against the Holy Spirit means or includes, it must wait until a future age to be forgiven. This seems to indicate that people who have committed this sin will miss reigning with Jesus in his kingdom, will not be resurrected until the final age begins, so will be among the last to be prepared for eternal fellowship with God.