Hayan bin Ubaidullah Adawi narrates: Once we were sitting with Hazrat Abdullah bin Buraidah (may Allah be pleased with him) when the muezzin gave the call to prayer (adhan) for the Zuhr prayer. When Sayyiduna Abdullah (may Allah be pleased with him) heard the adhan, he said: "Get up and perform two voluntary (nafl) rak'ahs before the iqamah." Because my father has narrated this: The Prophet Muhammad (peace and blessings be upon him) said: "Except for the Maghrib adhan, between every two calls (i.e., between the adhan and the iqamah), two rak'ahs should be performed before the iqamah." Abdullah bin Buraidah says: I have seen Sayyiduna Abdullah bin Umar performing these two rak'ahs even at the time of Maghrib; he would never abandon them under any circumstances. The narrator states: We got up and performed two rak'ahs before the iqamah, then we waited until the Imam arrived, and then we performed the obligatory prayer behind him. Husain Mu'allim, Sa'id Jariri, and Kahmas bin Hasan have narrated contrary to this; all these narrators are trustworthy, whereas the narrator named Hayan bin Ubaidullah is not very reliable. And Allah knows best.