A God who repents, who changes his mind, cannot truly be a God because a true God is by definition unchangeable and never undergoes any mutation. Moreover, if God destroys his own creatures because they are evil, then God himself must be the origin of evil, which is – again – not worthy of a God. To Celsus, and many anti-Christians after him, the concept of God is fundamentally flawed.
https://aeon.co/essays/why-would-apollo-make-positive-statements-about-judaism