Abu Jurayy (may Allah be pleased with him) narrates: I said: "Alayka al-salam (upon you be peace), O Messenger of Allah!" He (peace and blessings be upon him) said: "Do not say 'Alayka al-salam'; 'Alayka al-salam' is the greeting of the dead. Say 'Al-salamu alaykum' (peace be upon you)." I said: "Are you the Messenger of Allah?" He (peace and blessings be upon him) said: "I am the Messenger of that Allah who, when harm afflicts you and you call upon Him, removes it from you, and when you are struck by a year of drought and you call upon Him, He makes things easy for you." I said: "Give me some advice." He (peace and blessings be upon him) said: "Never revile anyone, never regard any good deed as insignificant, and speak to your brother with a cheerful face. Raise your lower garment to the middle of the shin, and if you are unwilling, then to the ankles. Beware of letting the lower garment hang down, for it is part of arrogance, and Allah does not love arrogance. And if someone insults you with something he knows about you, then do not insult him with what you know about him, for its evil consequence will fall upon him alone."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6356