Participating in the National Day Celebration and the Evidence Cited for It

Question:
He says: Honorable Shaykh, may Allah grant you success. One of the students of knowledge in a country other than this one participated in the celebration of his country's National Day. When we rebuked him for that, he cited evidence, including that this act is a way of thanking Allah for the blessing of liberating the country from the hands of the enemies. He also cited the story of Musa and his fasting on the day of 'Ashura, and the hadith of the Prophet (peace and blessings be upon him) Are his arguments valid?

Answer:
These arguments are invalid, because thanking Allah is not done by establishing a festival. Thanking Allah is done through praise and eulogy, or through the prostration of gratitude when a blessing is renewed or a calamity is averted. The fasting of Musa is based on specific evidence. We do not invent things on our own; we do what the Prophets (peace and blessings be upon them) did, so we only fast and do not establish festivals or anything else. It is not permissible to designate a festival for the day of 'Ashura; it is not permissible, but we only fast. It appears that this person is either ignorant or has been misled. Yes.