By His wisdom, God gave preference to some places and times over others. For Muslims, Friday is the best day of the week, Ramadan is the best month of the year, “Laylat al-Qadr” is the best night in Ramadan, the day of “Arafah” is the best day of the year. Likewise the first ten days of the month of “Dhul-Hijjah” are the blessed days for Muslims.
God says in the Qur’an what means:
By the daybreak, by the ten nights, by the even and the odd, by the passing night – is this oath strong enough for a rational person? (Al-Fajr 89:1-5)
Early Muslim scholars differed on what is meant by the “ten nights”. But most of them agreed that the ten nights refer to the first ten days of Dhul-Hijjah.