"He is Allah, besides Whom there is no god; the King, the Holy, the Giver of peace, the Granter of security, Guardian over all, the Mighty, the Supreme, the Possessor of every greatness Glory be to Allah from what they set up (with Him)." (Quran, 59:23).
"Al-Salam" means: the One Who is free from defect and shortcoming, Whose qualities are above deficiency, Whose deeds are free from evil. Since He is as such, there can be neither peace nor security in existence without Him.
"Salam" means peace. Allah Almighty has said, "... and Allah invites to the abode of peace" (Quran, 10:25), meaning Paradise: anyone who abides therein will have been saved from agony and perdition. Allah has said, "And if he is one of those on the right hand, then peace to you from those on the right hand" (Quran, 56:90-91), that is, rest assured that they are enjoying peace and tranquility.
"Salam!" is a greeting; if a Muslim tells another Muslim "As-Salamu Alaikum!" he will have assured him of safety and security, granting him immunity against his evil or ill intentions. Allah Almighty praises Yahya, John the Baptist, by saying, "And peace be on him on the day he was born..." (Quran, 19:15).
The most precarious situations to which human beings are exposed are three: The time of birth, the time of death, and the time of resurrection. So Allah honored Yahya in all these three situations, granting him peace, safety and security against their woes. He saved him from the perils of all these three situations and granted him security against fear. Muslims are repeatedly enjoined by the Holy Quran to disseminate peace and to be receptive to those who offer it:
O you who believe! Enter into peace one and all... (2:208) And if they incline to peace, do incline to it too and trust in Allah. (8:61) And the servants of al-Rahman are the ones who walk on earth humbly, and when the ignorant ones address them, they say: Salam (Peace)! (25:63) And when those who believe in Our Signs come to you, say: Peace be on you! Your Lord has ordained mercy on Himself... (6:54) So turn away from them and say, Peace! For they shall soon come to know. (43:89)
Allah's Salam is His speech. Likewise, the Messenger of Islam used to quite often enjoin the believers to disseminate the greeting of peace among them. There are numerous traditions testifying to this fact; among them are the following: Assalamu minal Islam: The greeting of peace is an integral part of the creed of Islam.
Afshu al Salama taslamu: Disseminate the greeting of peace among you so you may achieve peace and security. Whoever upholds three things will have combined in him the meaning of conviction: 1) fairness to his own self, 2) disseminating of the greeting of peace to everyone, and 3) spending wisely out of what he saves. Afshu al Salama baynakum: Disseminate the greeting of peace among you.
In one of his supplications, the Messenger of Allah used to say, "Lord! Make us harbingers of peace to Your friends!" The Holy Quran tells us that the name of Paradise is "Dar al Salam," the abode of peace; He, Glory and Exaltation to Him, says, "They shall have the abode of peace with their Lord, and He is their guardian because of what they did" (Quran, 6:127).
Allah will make the greeting of the believers, when they meet Him, "Peace!" He says, "Their salutation on the Day they meet Him shall be: Salam! (Peace!)" (Quran, 33:44).
Referring to the believers, He says the following in Surat al- Ra`d, "... the gardens of perpetual abode which they will enter along with those who do good deeds from among their parents and spouses and offspring, and the angels will enter upon them from every gate (saying): Peace be on you because you were constant! How excellent, then, is the issue of the abode!" (Quran, 13:23-24).
Thawban, servant of the Messenger of Allah, has said, "Whenever the Messenger of Allah finished his prayers, he would seek forgiveness of Allah thrice, saying, `Lord! You are the Peace; from You is the Peace; Glory to You! Greatness and Honor are in You!'"
He who repeats this Name 160 times to a sick person will help him regain health.