وعن أبي هريرة رضي الله عنه عن
النبي صلى الله عليه وسلم قال: لما خلق الله تعالى آدم عليه السلام قال: اذهب فسلم على أولئك (نفر من الملائكة جلوس) فاستمع ما يحيونك، فإنه تحيتك وتحية ذريتك. فقال: السلام عليكم فقالوا: السلام عليك ورحمة الله، فزادوه: ورحمة الله
The Prophet (sallallahu alayhi wa sallam) said, “When Allah created Adam (sallallahu alayhi wa sallam), He said to him: ‘Go and greet that company of angels who are sitting there – and then listen to what they are going to say in reply to your greetings because that will be your greeting and your off-spring’s.’
Adam (sallallahu alayhi wa sallam) said to the angels: ‘As-Salamu Alaikum (May peace be upon you).’ They replied: ‘As-Salamu Alaikum wa Rahmatullah (May peace be upon you and the Mercy of Allah).’ Thus adding in reply to him: ‘wa Rahmatullah (and the Mercy of Allah)’ to his greeting.”.