It is narrated from Sayyiduna Abdullah bin Salam (may Allah be pleased with him), he says: We were walking with the Messenger of Allah (peace and blessings be upon him) when he heard people saying: "O Messenger of Allah! Which deed is the most virtuous?" The Prophet (peace and blessings be upon him) said: "To have faith in Allah and His Messenger, to strive in the path of Allah, and Hajj Mabroor (an accepted pilgrimage)." Then a voice was heard from the valley, someone was saying: «أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ» . Upon hearing this, the Messenger of Allah (peace and blessings be upon him) said: "And I also bear this testimony, and I also bear witness that whoever gives this testimony will be free from shirk (associating partners with Allah)." Imam Ahmad's son, Abdullah bin Ahmad, said: I heard this hadith directly from the narrator Haroon.