Based on an authentic tradition, before starting prayers, which is better to recite, adhaan or iqamah?
Recitation of both Adhan and Iqamah prior to every obligatory prayer(performed individually or in congregation) is highly recommended. There are several ahadith which elude to their merits. Below is one such hadith and possibly the one you were referring to:
Imam As-Sadiq (peace be upon him) has said: “One who offers his prayers along with Adhan and Iqamah, two rows of angels pray behind him, while one who offers his prayers with only the Iqamah and without the Adhan, one row of angels pray behind him.” The Imam (peace be upon him) was asked: “And how long is each row?” The Imam (peace be upon him) replied: “At the very minimum, its length is the distance between East and West, while at the maximum, its length is the distance between the earth and the heavens.”
Wasa’ilush Shi`a, Volume 4, Page 620
Answered by: Dr Ali Alsamail
Certified by: Sheikh Mansour Leghaei