In the Parsha it says repeatedly G-d hardened Pharoah's heart. This raises the question whether it is ever too late to have
free will to serve G-d.
The Rambam says that there are times when a person does a sin in such a way that he is actually
prevented from doing teshuvah, repentance.
In such a case it is necessary for a person to pray sincerely for free will not to be removed from him and
the opportunity to see things in such a way that he will be able to do teshuvah. Without such prayer
he is actually prevented from repenting. [It could be that only
from a different state of mind or level of consciousness will a person really understand the extent and
meaning of what was wrong about the sin.]
The Talmud speaks about Reb Elazar ben Durdai, who sinned his whole life and then repented by
asking the sun and the mountains, etc. to intercede on his behalf, which they refused, and then finally he
prayed himself fervently until his soul left him, whereupon it was heard in heaven that Reb Elazar ben Durdai
had a place in the eternal world.
The mussar teachers therefore teach that it is never 'too late.'
- based on R. Reisman's motzai shabbos shiur 1/16/99