I’m not suggesting it is unforgivable but only unforgivable in the natural man remaining in unbelief. If Saul would have remained natural, never born of the Spirit of God. As the example of Saul and Paul. As the example of the old man and the New Man. Maybe I am still not understanding you because what it seems you are saying is that when the word says walk in the Spirit and you will not fulfill the lust of the flesh. That this walking in the Spirit is capable of blasphemy? Have I misunderstood? As He said “I will be in them and walk in them”. You keep referencing the natural man and the carnal as if they are the Spirit and therefore the Spirit can fail or come short of the end. 1 Corinthians 3:1-3 And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ. [2] I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able. [3] For ye are yet carnal: for whereas there is among you envying, and strife, and divisions, are ye not carnal, and walk as men?
Get the “babes in Christ” but also see “and walk as men”...urging to and out from “and walk as men” “hereto not able to bear it, neither yet now are you able.” So, I don’t understand how “babes in Christ” not able to bear and still unable; becomes that born of the Spirit of God is capable of blasphemy? When the Spirit
1 Corinthians 13:7-8 Beareth all things, believeth all things, hopeth all things, endureth all things. [8] Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away.
Even Christ told them He had many things to tell them but they were not yet able to bear it. John 16:12 I have yet many things to say unto you, but ye cannot bear them now.