Ulema have warned against mistakes being made during Taraweeh prayers by some Imams leading the prayers and by some worshippers as well. They stressed the necessity for Imams in particular to follow the Sunnah of the Prophet (peace be upon him) and his companions after him. Dr. Ibrahim Bin Saleh Al-Khudhairi, Judge of the Court of Cassation in Riyadh, stressed the importance of following the Sunnah in performing Taraweeh prayers. At the same time he urged Imams not to blindly imitate some well-known Qur'an reciters. Sheikh Al-Khudhairi stressed, “Taraweeh prayer must not be performed in haste nor should Imams imitate Qur'an reciters attempting to reproduce their beautiful voices and other minute details of their recitation.” He also warned against the improper use of echo sound systems that repeat a sentence several times, which is inappropriate. “If sound devices have the effect of distorting the Qur'an recitation, then it is impermissible to use them. However, if it just to beautify the voice and enable people to hear, then it is permissible,” he said. Al-Khudhairi called on Imams to observe moderation and not to prolong prayers, as there are children and people who are weak, sick and old among the worshipers in addition to those who want to leave to attend to other matters. Taraweeh prayers are performed after Isha prayer during the holy month of Ramadan. The number of Raka'a during Taraweeh vary from 11 to more, at the end of which the Imam makes the Qunoot supplication. It is narrated that the Prophet (peace be upon him) and his companions after him performed Taraweeh prayer in congregation. Dr. Saud Al-Fenaisan, former Dean of the College of Shariah in Imam Muhammad Bin Saud Islamic University, said among the mistakes that are made by some Imams and worshippers is that their aim is to complete the whole Qur'an as fast as possible – hence there is speed at the expense of contemplation of the verses of the Qur'an. Dr. Adnan Baharith, Associate Professor of Education at Umm Al-Qura University, stressed that the mosque has its sanctity and this must be respected. People must not treat a mosque like a public park. Also, children should not be in the front rows near the Imam so as not to disturb him and the worshipers. Also, both children and worshipers must observe the purity of mosques. Dr. Anas Bin Sa'eed Bin Misfir, Professor of Aqeedah (creed) at Umm Al-Qura University, said Imams should fulfill their duties. He said the Saudi Ulema have issued a fatwa (edict) saying that it is impermissible for Imams to leave their mosques and go to perform Umrah, since Imams must be responsible and carry out their duties.