This has nothing to do with purgatory. That is an idea you are bringing to the text.
Leaving aside what "speaking blesphemy against the Spirit" means, Christ says it will never be forgiven in this life or the next.
Paul writes in Corinthians that the works of believers - the saved - will be tested by fire. Obviously, to be a believer, you would have to be forgiven of all your sins. Failing that, you won't be rewarded for works. Ergo, these believers never blasphemed the Spirit.
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Do you have any evidence from before 100ad that supports your claims? If so, it would be great if you would share it here for us all to discuss.