These dates were simply a recording of the time interval between which He manifested His eternally divine pastimes, to the mortal world, during the Age of Dvapara (the prior to the present Age of Kali).During that time, He spoke the Bhagavad-gita (the greatest transcendental message of all times) to Arjuna, but this does not limit His position as the adi-purusha (the original Supreme Person) and the adi-guru (the original teacher).
In the Vedic literature Lord Krishna is described as the ultimate source of all knowledge; hence, He is also the most reliable source of knowledge and the greatest well wisher of all the living entities.The whole guru parampara (the disciplic succession) begins from Him. There are many incarnations of Lord Krishna. Each one is scheduled and forecast within the Vedas themselves, and manifest within this material world in order to teach by example the path to spiritual emancipation.
In the Western countries, when somebody sees the cover of a book like Krishna, they immediately ask, “Who is Krishna? Who is that girl with Krishna?” etc. The immediate answer is that Krishna is the Supreme Personality of Godhead. How is that? Because He conforms in exact detail to descriptions of the Supreme Being as mentioned in the infallible Vedic scriptures.
In other words, Krishna is the Godhead because He is all-attractive. Outside the principle of all-attraction, there is no meaning to the word Godhead. Krishna is the unlimited possessor of all the 6 opulences namely, strength, fame, knowledge, wealth, renunciation and beauty. His beauty exceeds the beauty of billions of Cupids (god of lust). Therefore the name Krishna itself means “all attractive”. In other words Krishna is able to attract anything within the entire creation. He is the Supreme Absolute Truth and His Divine Lotus like Feet is the ultimate goal of all the living entities.