Why did the asceticism of Umar ibn Abd al-Aziz not become manifest until after he assumed the Caliphate, even though a believer is ascetic in all circumstances?

There is no justification for asking about the reason for Umar ibn Abd al-Aziz’s asceticism after assuming the Caliphate, for guidance is in the hands of Allah. However, it can be said that the feeling of the immense responsibility of the Caliphate changed his state for the better and diverted from him the evil of the world. Moreover, his yearning soul longed for the highest stations until it reached the Caliphate, and then it yearned for Paradise.