Last month of the Islamic Calendar.
Meaning - The month of "Hajj" (Pilgrimage). This is the last sacred month in which fighting was forbidden.
Blessings
The fifth pillar of Islam "Hajj" is performed in this sacred month. The first 10 days of Zul-Hijjah are the most virtuous days in this whole month, Hajj is performed amongst these 10 days.
Hadhrat Abu Haraira (R.A) reports from the Holy Prophet : "Amongst all days there are none better to engage in worship of Allah than in the 10 days of Zul-Hijjah, To observe a fast on any of these days is equivalent to fasting throughout the year, to actively engage in prayer and worship throughout any of these nights holds such rewarding values leveling with "Night of Power" (Laylatul-Qadr) - "Tirmizi"
It has been stated in the Holy Quran, "By the dawn; By the 10 Nights (ie. the first 10 days of the month of Zul-Hijjah), and by the even and the odd (of all the creations of Allah) and by night when it departs. There is indeed in them (the above oaths) sufficient proofs for men of understanding. (and that they should avoid all kinds of sins and disbelief)"
Hadhrat Abu Qataadah (R.A) reports in a part narration from the Holy Prophet concerning the fast observed on the day of Arafaat : "I have full confidence in Allah for the one who observes a fast on the day of Arafaat that his previous year's sins and the proceeding year's sins are forgiven." - "Muslim"
Events
1. The Prophet performed the farewell Hajj and gave the historic sermon known as the "Farewell Sermon"
2. Egypt was conquered by the army sent by Hadhart Umar (R.A.)
3. Uthmaan (R.A.) was appointed the third Caliph
4. "Bayat-e-Aqabah"
5. Hadhrat Umar (R.A.) met martyrdom - 27th of Zul-Hijjah in the year 26 A.H.