Prayer: Sufficing with Another Person's Adhan and Iqamah
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 914
If someone hears another adhan and iqamah – irrespective of whether he repeats after them or not – then, in the event that the interval between that adhan and iqamah and the prayer that he wants to perform is not long, and he had the intention to perform prayers from the time he started hearing them, he can suffice with that adhan and iqamah. However, if only the imam or only the followers of a congregational prayer hear the adhan, this rule is problematic [i.e. based on obligatory precaution, he cannot suffice with it].