PEACE IN ISLAM
Islam is derived from the Arabic root word “salaam” which means peace, purity, submission and obedience. Therefore, Islam means submission to the will of Allah and obedience to His law. Peace refers to the absence of hostility, the absence of ego. One can attain eternal peace only after submitting his will to the Allah The Almighty. 
The word Peace is derived from the root word S-L-M. The scholars of language mention four closely related terms that can be derived from this origin: Salam, Salamah, Silm, and Salm.
Peace is the basic requirement for our existence and a pathway to attain success in both the worlds. Whenever a Muslim meets another Muslim, they greet each other with the Islamic greeting “Assalaam-u-Alaikum” which means “peace be upon you” and the other person replies saying “Walekum-assalaam” meaning “peace be upon you too”.
Islam is "submission to Allah, accepting His authority as well as obeying His orders"; "one's total submission to Allah and serving only Him"; "embracing the messages of the Prophet Muhammad (صلى الله عليه و سلم) and abiding by them." In this sense, a Muslim is one who is under the peaceful and safe shade of Islam. Allah wants a Muslim to live in a safe and peaceful environment and to make efforts for the spread and continuity of peace. 
Real happiness and peace can be found in submitting to the commands of the Creator and the Sustainer of this world. Allah has said in the Quran: Truly, in remembering God do hearts find rest. Qur’an.Surah R’ad 13:28
“But if the enemy incline towards peace, do thou (also) incline towards peace, and trust in God: for he is One that heareth and knoweth (all things).” Qur’an. Surah Anfal 8:61
“If thou dost stretch thy hand against me, to slay me, it is not for me to stretch my hand against thee to slay thee: for I do fear God, the cherisher of the worlds.” Qur’an.Surah Maeda 5:28
"God does not forbid you from showing kindness and dealing justly with those who have not fought you about religion and have not driven you out of youar homes. God loves just dealers.” Qur’an.Surah Mumtahina 60:8
In the Qur'an, it is recommended to cease disagreements by peace and not to commence further disputes, fights, confusion, and discord; in addition, people are asked to take a balanced approach and seek justice. Qur'an.Surah Anfal 8:1; Surah Hujrath 49:9–10. 
Islam promotes peace from the very ground level. All of us should practice peace at individual level, a nation-wide or world-wide revolution is not the solution at all times. We should aim at changing ourselves, our environment, the society we live in, our neighbours, the poor around us. We can achieve peace at individual level by helping those in need, sorting out problems of our near and dear ones if any, feeling the poor, speaking well to our servants, etc.
An ayath from the Qur’an talks about the immense importance of life of an individual. “For that cause We decreed for the Children of Israel that whosoever kills a human being for other than manslaughter or corruption in the earth, it shall be as if he had killed all mankind, and whoso saveth the life of one, it shall be as if he had saved the life of all mankind.’ Qur’an Surah Maidah 5:32.
The Qur'an emphasizes peace and reconciliation as basic to all social and even international relations. As mentioned in the Qur'an, Paradise, which is the reward for the pious, is a place of serenity. One of the names of Allah is Salaam, which means Peace. Throughout history, Muslims have made every effort to establish peace and serenity everywhere in all divergent fields, only taking military measures when their enemies tried to hinder these efforts for humankind. Over the course of history, the general approach of Muslims has been supportive of maintaining peace, spreading an environment of serenity and trust, and constructing a civilization of love, compassion, and mercy to share with other people in peace.