It means after a death we all become ONE. One to our creation itself known as ‘Brahma’. This text is written in our various ancient Hindu Veda. Because in our Hindu culture it is always believed that bodies are like clothes which we wear for some time until our energies decay and once death arrives, our soul is finally liberated from the cycles of life & death.
In India, you might have heard stories or even your daadi or naani chanting “Om Shanti” or “Mukti” or “Moksha” on a daily basis because our older generations always knew that we are bound by Karma & Maya in our life and we all will be free to our final liberation that is ‘Jivan Mukti’.
But as the times are changing and English education is becoming a source of learning, we are also adjusting to the westernized culture. That’s why saying “RIP” to someone after their death became a habit in many modern cities. Even many of us are saying without even knowing where it comes from.
So now let’s understand why Hindus should say “Om Shanti” than Rest In Peace after someone dies.
Because in many religions like Christianity people use to say ‘Rest in Peace’ after anyone dies because they believe that after death their souls will wait until ‘Judgement Day arrives. So that’s why they believe the soul must rest in peace until judgment day comes.
But in Hinduism, we always believed in karma & Moksha. That’s why even our last rites that go on for like 13 days are focused to destroy the present life karma and we pray to god to guide the soul (jiva atma) to a better next life in its next birth.
So having such core teachings of life & death, our Hinduism culture always believed that in realizing the true nature of jiva atma & parmatma , our liberation is assured. That’s why we Hindus always say “Om Shanti” which means may this soul attains liberation. Om here means the presence of creator itself & ‘Shanti’ is said for ‘atma’ (soul) to calm down the soul that gets disturbed by the trauma of leaving the body.
Our Hinduism is the oldest culture present on this planet right now so when you are a part of such an old heritage of spiritual and religious teachings, it’s our responsibility to have clarity in our legacy (amaanat) given as culture to us & also teach our children about it.