It is narrated from Sayyiduna Abdur Rahman bin Awf (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) went out, (I also followed behind). The Prophet (peace and blessings be upon him) entered a garden, and there he began to pray, and he performed such a long prostration that I began to fear that perhaps his soul had been taken. I moved forward to see, and the Prophet (peace and blessings be upon him) raised his head and said: "Who is it?" I replied: "Abdur Rahman." The Prophet (peace and blessings be upon him) said: "Abdur Rahman! What happened?" I mentioned my concern, upon which the Prophet (peace and blessings be upon him) said: "Jibreel came to me and gave me the glad tidings that Allah Almighty says: Whoever sends blessings upon you, I will send mercy upon him, and whoever sends peace upon you, I will send peace upon him, that is, I will grant him safety. Upon this, I performed a prostration of gratitude in the presence of Allah."