What is the ruling regarding the action of a person who rushed to cover his father, whereupon his father yelled at him and insulted him, so the son swore he would not serve him that day, and then broke his fast, thinking that God was angry with him and would not accept his fasting?

A person must repent for causing harmful haste to the father and seek his forgiveness, and for his harshness, as it is not permissible for him to be harsh towards his father or harm him with words. He must feel remorse and resolve not to return to what he did. It would have been better for him to repent and complete the fast, not to break it, while bearing in mind that if he intended good by the haste, he should have softened his words.