The Grand Ayatollah Shobairi Zanjani answered a question about observing the limits of Tajweed (rules for correct recitation of the holy Quran) in Salaat.
Question: To what limits Tajweed needs to be observed in Salaat?
The Grand Ayatollah Shobairi: Observing the correct pronunciation and the right movements of the letters to an acceptable level are needed, but observing those groups of rules of Tajweed which make the recitation more beautiful, and even without them it is commonly said that the Arabic pronunciation is correct, it is not needed.
Source: PERSIAN SHAFAQNA
source : en.shafaqna.com
