Hilchot Teshuva 6:1-3 (Verses that State that G-d Prevents Repentance)

In our last shiur, we learned that the Rambam declares unequivocally that every human being is granted the freedom to choose to be good or evil. If that’s true, how can we explain the many verses in the Torah – such as G-d’s hardening Pharaoh’s heart – which seem to imply the opposite?