How can one respond to those who claim that the rituals of Hajj can be performed in any month of the known months, citing Allah’s saying: "The Hajj is [during] well-known months," and not necessarily in the month of Dhul-Hijjah?

To respond to those who distort the religion, Allah Almighty commanded the following of the Messenger (peace be upon him) and adhering to what he brought. The Prophetic Sunnah is like the Holy Quran in the obligation of adherence. The Prophet (peace be upon him) clarified the Hajj and its methodology. So, whoever opposes the Messenger and follows a path other than that of the believers, Allah threatens them with Hell.