Question: why is dhul hijjah important?
Answer: Allah swore by the ten nights (i.e. the first ten days of Dhul-Hijjah) in Qur'an 89:2. During these days, all the major acts of worship are performed- prayer, fasting, charity and pilgrimage. The ninth day of Dhul-Hijjah is the day of Arafah. ... It is the most crucial event of Hajj.