If you know that someone is from God, you have evidence of their spiritual power, and you are a beneficiary of that power, you cannot claim not to know who their God is. If you are not a beneficiary of their spiritual power, you nonetheless have an obligation to inquire of the Lord as to the source of their power, prior to your making comments or issuing proclamations in regard thereto.
God cannot forgive Blasphemy. It is a sin that is committed against the ether in the planet, and therefore, only someone in the planet with authority from God can forgive it. The lesson to be learned is that when the Holy Spirit Of God tells you to do something, do it, whether or not you understand the reason.
The Lord God Almighty El Shaddai