Yusuf bin Abdullah bin Salam narrates from his father (Sayyiduna Abdullah bin Salam, may Allah be pleased with him): Once we were sitting with the Prophet Muhammad (peace be upon him), when the Prophet (peace be upon him) heard people saying, "O Messenger of Allah! Which deed has the most virtue?" The Prophet (peace be upon him) said: "To have faith in Allah and His Messenger, to strive in the path of Allah, and a righteous Hajj." Then the Prophet (peace be upon him) heard a voice in the valley saying, "I bear witness that there is no deity except Allah, and indeed Muhammad (peace be upon him) is the Messenger of Allah." So the Prophet (peace be upon him) said: "I also bear witness to this, and I also bear witness that whoever bears witness to this will be free from shirk."