What is the jurisprudential ruling on taking twenty thousand from one's mother upon success in the baccalaureate exam?

Allah has urged His servants to fulfill covenants and promises, and a promise is part of a covenant. In the Hadith (definition): "The signs of a hypocrite are three: if he promises, he breaks it." And liars are known by their breaking of promises. Ibn Hazm said: "Whoever promises another person that he will give him a specific or non-specific amount of money is not obligated to fulfill it, and it is disliked for him to do so. It would have been better had he fulfilled it."