What is tajweed? It refers to the rules governing pronunciation during recitation of the Qur'an. The importance of Tajweed: And recite the Quran with measured recitation."[Quran 73:4] Muhammad bin Al-Jazaree the great Qur'an and Hadeeth scholar of the 9th Century (Hijri) says in his famous poem detailing the rules of Tajweed: "And applying Tajweed is an issue of absolute necessity, Whoever doesn't apply Tajweed to the Qur'an, then a sinner is he." Sheikh Zakariyyaa Al-Ansari [died in 926 H.] said in explanation of this verse in his book: Sharh al-Muqaddimah al-Jazariyyaa "It is required to observe all of the Arabic rules in that which changes it and ruins the meaning".