Arcana Coelestia#8151
8151. 'And Jehovah hardened the heart of Pharaoh [king of Egypt]' means obstinate opposition from the falsity that arose from evil. This is clear from the meaning of 'hardening the heart' as behaving obstinately, dealt with in 7272, 7300, 7305, 7616. When it says that Jehovah hardened his heart the meaning in the internal sense is that those steeped in evil and falsity hardened themselves, thus that the actual evils and falsities did so. On this matter see 2447, 6071, 6991, 6997, 7533, 7643, 7877, 7926.
Arcana Coelestia#7305
7305. 'Pharaoh's heart is inflexible; he refuses to send the people away' means that they were obstinately determined not to leave those whom they were molesting. This is clear from the meaning of 'heart is inflexible', also 'unyielding' and 'hardened', as obstinacy, as above in 7272, 7300; from the meaning of 'refusing to send away' as not leaving; and from the representation of 'Pharaoh', about whom these things are said, as those who engage in molestation, dealt with previously.