I think that you are a bit flippant with the use of the word blasphemy.
It would seem that the only safe position that you would offer is that we deny any leading of the Holy Spirit and totally walk by sight.
People are going to make mistakes, the enemy is going to fool us at times, but does YHWH want us to never accept a nudge from the HS just so that we can never possibly be wrong?
"Walking by sight" biblically is contrasted with walking by faith. Modern English-speaking culture usually refers to "faith" as "faith in yourself" or some kind of general faith and confidence in what you think. According to Scripture he that trusteth his own heart is a fool, and also someone who puts their trust in the words of man. Basically believing what you or any other man believes is right just for the sake of believing them and for no other reason is putting your trust in them. Basing your perception of truth and morality on such trust is sin, and is cursed by God. It is the chief sin of the Catholic church and the Muslims as well.
It is perfectly fine to think that God has blessed you, and is helping you do something; it is fine to think that God worked something out, or wants you to do something, as long as you acknowledge that it is you yourself thinking that. When you say "God says" you have gone to a completely different level, yet this has almost become a figure of speech. Though I suppose most people, if you pursued the point, would not claim that they infallibly know what they think is true or that what they think is equal to Scripture, but like the example given in this thread some will in fact argue their own convictions against Scripture.
God guides us by his Spirit, but in the way he says he guides us: we cannot claim just anything as his guidance. Everything we do right we do by his power, but of course we do not always do right. In the same way all that we think rightly we think by his guidance, and it does not mean that we always think right.
"Wherefore I give you to understand, that no man speaking by the Spirit of God calleth Jesus accursed: and that no man can say that Jesus is the Lord, but by the Holy Ghost." - I Corinthians 12:3
Thus someone who has exercised his senses by use to discern good and evil has more guidance from God, but this is simply another way of saying that he follows God's guidance more. In a disagreement, saying that one is following God's guidance is no more a reasonable argument than simply saying "I'm right", unless one is claiming to have some direct revelation, which must be backed by miracles.
Great point.... how many thought the prophets to be false because they proclaimed seeming impossibilities the Lord told them that did not happen in their lifetime?
Sounds a bit like modern rabbis who reject Yeshua because he prophesied things that have not yet happened. They declare him a 'false prophet'.... truth is that often time is the unaccounted for ingredient. ..
I ask for a second witness or patiently wait... the Father is the only true judge that can identify false prophets. If we aren't sure, we need to compare with Scripture and wait...
The Father commanded us to judge false prophets and to try the spirits. One way he gives is of course to test if they contradict God. The other was if something they say does not come to pass: "When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him." - Deuteronomy 18:22
Obviously this is cannot be used for prophecies that have no specified time when they will be fulfilled. Most if not all the prophets as I recall gave or were asked for "signs that these things will come to pass", that is, they gave a soon or immediate miracle to prove that prophecies of a further or more undefined future time would come to pass. If there was a case where they didn't "confirm the word with signs following", they could not called a false prophet, but they could not be called a prophet either until their prophecy was proven one way or the other.
In any case Yeshua did more miracles to prove his inspiration than probably all the prophets combined, and the apostles may have done even more than he did as he told them that greater works would be done after he returned to the Father. Modern rabbis who reject Yeshua don't have a leg to stand on.