Is there any difference between liberation and realization, or are they absolutely identical?
There is a great difference between liberation and realization. Liberation is much inferior to realization. One can reach liberation in one incarnation, and realization in some later incarnation. Or one can become liberated and realized in the same incarnation. But it is not possible to be realized without first being liberated. Sometimes a great spiritual Master, if he is fortunate, will bring down with him a few really liberated souls to help him in his manifestation. Sri Ramakrishna, for example, brought down Vivekananda and Brahmananda. Some of these liberated souls who enter the earth-scene with the great Masters do not care for realization. They come just to help. Others, like Vivekananda and Brahmananda, want realization also.
A liberated soul is liberated from ignorance, from worldly, undivine qualities. A liberated soul will inspire others with his presence. He will inspire them to be pure, simple, kind-hearted and loving. Tremendous purity and serenity will flow from him, and others will want to touch him, speak to him, look at his face. You can say that he is much more than a saint. True, worldly obscurities, impurities and other things will not enter into the liberated soul, or he will be all the time cautious so as not to allow them to enter into him. But a realized soul is much higher. He is consciously part and parcel of God.
Realized souls are extremely powerful. They know what they are and where they have come from. On the strength of their universal and transcendental consciousness, they can enter into the ignorance of humanity, into the earth-consciousness as such, and illumine it with their light.
A liberated soul is like a child, so beautiful and pure. But how long can you stay with a child? With his capacity you cannot go very far, or reach the Highest. A realized soul is like a mature person who can offer you tremendous aspiration, light and wisdom, the living reality. A liberated soul will inspire you to walk along the path. A realized soul will not only inspire you, but also guide you and lead you to your destination.