`Alayhi-salam means 'Upon Him Be Peace OR Peace Be Upon Him'. It is a respectable phrase said after mentioning a Prophet or Messenger of Allah صلى الله عليه و سلم. It is often represented by the acronym (AS), or the English acronym of Peace Be Upon Him (PBUH).
Arabic - عليه السلام
Prophets of Islam are those humans chosen by Allah سبحانه و تعالىand given revelation to deliver to mankind. Muslims believe that every prophet was given a belief to worship the only God i.e., Allah سبحانه و تعالىand their respective followers believed it as well. Abu Zarr(R) narrated that Prophet Muhammad ﷺsaid: Allah سبحانه و تعالىhas sent many prophets and from them 315 were the Messengers, Musnad Ahmad 21552, 21546, silsilatul sahiya, 2668, classed as saheeh by al-Albaani.
Allah سبحانه و تعالىhas send all the messengers and prophets with a common message i.e., to believe in Allah سبحانه و تعالىand avoid worshiping other things. “And We did not send any Messenger before you (O Muhammad ﷺbut We revealed to him (saying)): La ilaha illa Ana [none has the right to be worshipped but I (سبحانه و تعالىAllah)], so worship Me (Alone and none else)."Qur’an.Surah Anbiya 21:25. Muslims believe that all prophets gave guide lines and instructions to their people about how to properly worship Allah سبحانه و تعالىand live their lives. Since God is One, His message has been one and the same throughout time. In essence, all prophets taught the message of Islam - to find Peace in your life through submission to the One Almighty Creator i.e., to believe in Allah سبحانه و تعالىand to follow His guidance.
Stories of the Prophets by Ibn Kathir