What is the significance of saying "peace be upon you" (Al-Salam Alaykum) and "and upon you be peace" (Wa Alaykum Al-Salam)?

The traditional Arab greeting was "An'am Sabah" (Good Morning), but Islam legislated for Muslims the greeting "As-salamu alaykum" (Peace be upon you), which is a unique emblem for them. It signifies safety from evil and is one of Allah's Beautiful Names. Greeting with "Salam" is preferred over others because it encompasses safety, which is the essence of success. The Prophet, peace be upon him, made spreading greetings a part of faith, as it combines goodness in word and deed and plants affection and love in hearts. Spread peace among yourselves to achieve harmony and love and enter Paradise. The Prophet, peace be upon him, also clarified the great reward of the greeting: whoever says "As-salamu alaykum" receives ten good deeds; whoever adds "wa rahmatullahi" (and the mercy of Allah) receives twenty; and whoever adds "wa barakatuh" (and His blessings) receives thirty. Returning the greeting is obligatory, as it is a right of a Muslim upon another Muslim, and it signifies security and removes estrangement and severance.