It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that Sayyiduna Bilal (may Allah be pleased with him) used to initially call the adhan with these words: « أَشْهَدُأَنْلَاإِلَهَإِلَّااللهُ » "I bear witness that there is no true deity except Allah" « حَيَّعَلَىالصَّلَاةِ » (Come to prayer). So Sayyiduna Umar (may Allah be pleased with him) said to him: After « أَشْهَدُأَنْلَاإِلَهَإِلَّااللهُ » say « أَشْهَدُأَنَّمُحَمَّدًارَسُولُاللهُ » (I bear witness that Muhammad is the Messenger of Allah). Then the Messenger of Allah (peace and blessings be upon him) said: "Say it as Umar is commanding you."