"I believe that I cannot come to my Lord Jesus Christ by my own intellegence or power. But the Holy Spirit call me by the Gospel, enlightened me with His gifts, made me holy and kept me in the true faith,"
Not sure where you're getting that Martin Luther believed in a free will. I think the last we saw of free will was in the Garden of Eden before the Fall of man into sin.
to believe in His Son or not to, and even if believing in His Son, to nevertheless reject the salvation that His Son's blood offers.
Huh?
Sola Scripture unfortunately teaches in effect that believing by definition means relinquishing one's free will
Well surprise surprise... that's what the Bible says too. We can be slaves to sin or servants of righteousness. We are bought with a price, etc.
Despair is presumption's antithesis, and it haunted Martin Luther's earlier outlook, fueled by his supercharged scrupulosity, so he invented Sola Fide to keep himself from going batty. In no way, however, am I suggesting that he didn't correctly identify and justly decry some abuses that he observed within the Church.
My young sons, too, are wont to misbehave, but I work to correct them, not to lobotomize them, which is akin to the utterly false sola fide view of salvation.