Yasar narrates: Once, Abdullah bin Umar (may Allah be pleased with them both) saw me performing voluntary prayers after the true dawn had appeared. Abdullah bin Umar (may Allah be pleased with them both) said: "O Yasar! Once the Prophet Muhammad (peace and blessings be upon him) came to us while we were performing this same prayer (i.e., voluntary prayers at this time), and he said: Let all people convey this message to those present and those absent: After the true dawn has appeared, only two rak'ahs (the Sunnah) may be performed (no other prayer can be performed at this time)."