The following excerpt was taken from The Summits of God-Life: Samadhi and Siddhi by Sri Chinmoy.
Talk on Samadhi and God Realisation
Samadhi is a realm of consciousness. Many people have entered into samadhi, but realisation comes only when we have become one with the highest Absolute. We can enter into some samadhis without realising the Highest.
Entering samadhi is like knowing the alphabet, but realisation is like having a Ph.D. There is no comparison between samadhi and realisation. Samadhi is a state of consciousness in which one can stay for a few hours or a few days. After twenty-one days usually the body does not function. But once one has achieved realisation, it lasts forever. And in realisation, one’s whole consciousness has become inseparably and eternally one with God.
There are three stages of samadhi: savikalpa samadhi, nirvikalpa samadhi and sahaja samadhi. Savikalpa samadhi is an exalted and glowing state of consciousness, whereas realisation is a conscious, natural and manifesting state of consciousness. When realisation dawns, the seeker enjoys freedom from the human personality and human individuality. He is like a tiny drop of water which enters into the ocean. Once it enters, it becomes the ocean. At that time, we do not see the personality or the individuality of the one drop. When one realises the highest Truth, the finite in him enters into the infinite and realises and achieves the infinite as its very own. Once realisation has taken place, a Master can easily enter into savikalpa samadhi. Nirvikalpa samadhi, too, is not difficult for a God-realised soul to attain. Only sahaja samadhi, which is the highest type of samadhi, is a problem, even for the very highest God-realised souls.