sri-bhagavan uvaca
param bhuyah pravaksyami
jnananam jnanam uttamam
yaj jnatva munayah sarve
param siddhim ito gatah

"The Supreme Personality of Godhead said: Again I shall declare to you this supreme wisdom, the best of all knowledge, knowing which all the sages have attained the supreme perfection."

Sri Krishna tells Arjuna about the glory of the Gyana, He was to preach. Sri Krishna is a good orator and knows the techniques to attract audience! Pravakshyami = [I, Sri Krishna] will tell [you, Arjuna], bhuya = again, param = in a different way [about the difference between atman and body]. In Chapter 13, the Lord told so many things, important being how to distinguish atman from body. This is going to be further explained. That is, how atman is bonded in a body, by the three qualities, is going to be elaborated. The knowledge He was to deliver would make Arjuna a great expert. In Chapter 13, He had taught to some extent. Jnananam = among knowledge [to be acqui,red], utamam jnanam = most superior knowledge [is this, the Lord is about to teach]. Among the knowledge on prakruti and purusha or body and soul, this knowledge would be most superior. Swami Desika raises a doubt that normally Brahma Gyana or knowledge about God, is considered as the most supreme. But since the topic here is about atman, is the knowledge about atman, superior even to Brahma Gyana? It is not so. So, the Lord is going to teach most superior among all knowledge, excepting Brahma Gyana. Yaj jnatva = by knowing which, sarva munaya = all sages, ito = from this samsaram bondage, gata = attained, param siddhim = supreme level of atman prapti. The Lord is going to teach that knowledge, learning which, even great sages were able to escape from smsaram bondage and attain atman prapti. All other knowledge would not enable us to discard this samsaram and avoid rebirths, and reach Moksham. Muni means continuous meditating like Hanuman. They are great sages