Mahasukha alludes to absolute bliss that a spiritual aspirant (sadhaka) should work for in this world of incessant change and movement, characterized by pleasure and pain, love and hate, and life and death. Maha literally means great and sukha means happiness.
Mahasukha ought to be the supreme goal of human life according to Hinduism. It should be distinguished from the pleasures of the phenomenal world (samsara sukhas0 which are transient.
To experience everlasting peace and bliss, one needs to liberate oneself from the hassles of material life by remaining in the world but not involving oneself; it is like the lotus in a pond.
Everlasting freedom from pain or passion is possible only with the realization of God, who embodies supreme knowledge and bliss. The attainment of moksha or mukti (liberation), parama pada (reaching the highest pedestal of glory), and nirvanapada (attainment of eternal peace) – is mahasukha and understood as the art of dying while being alive.
To get this eternal peace, the aspirant is required to become atmavan (one who has true knowledge of the Self) by perceiving the unchanging reality behind the changing body, sense organs, mind and ego. The atman is indeed pure consciousness and beyond time and space, limit and causality. It is eternal and the real substance in every individual. The unchanging reality in the universe is called Brahman, which is beyond time and space, limit and causality. It is the all pervading spirit.
The Hindu philosophy of Vedanta states Brahman and atman are one and the same. The knowledge of this identity is called ‘Self-knowledge.’ It is the liberation from bondage and suffering.
Source:
Gems of Truth (1964) – Jayadayal Goyanka – The Gita Press Gorakhpur
Self knowledge of Acharya Shankara (1978) – Swami Nikhilananda – Shri Ramakrishna Math Chennai.