Krishna is the Supreme aspect of God that transcends all universes and is in constant unity with S'iva. Because they are inseparable we always think in terms of S'iva/Krishna.
When we say “Krishna,” we’re talking about God. Many people may think Krishna is a “different God” from the one they worship. But there’s only one Supreme Person, and Krishna is one of His names.
The name Krishna literally means “all-attractive.” So, not only is Krishna/God all-powerful and all-knowing, He’s also the most beautiful Person.
We are all parts of Krishna, just like drops of ocean water are tiny samples of the ocean. The more we know about Krishna, the better we understand ourselves, and the easier it is to understand the purpose of our life.
The Vedas say Krishna is the original person, but that He always appears young and attractive. He knows everything, He contains all of reality, and all other living beings are His inseparable parts. He is the all-powerful, supreme controller of all energies. He is known by different names in different cultures (such as God, Allah, and Jehovah).
Sometimes Krishna sends His representatives - as saints or prophets to teach humankind about Him, and sometimes He comes Himself, as He did approximately 3000 B.C. He spoke the spiritual and philosophical teachings known as the Bhagavad-gita, which explains the essence of our spiritual identity and our relationship with God.
Krishna frequently visits Earth, in as many avataras or incarnations as the ocean has waves. He either comes Himself, sends representatives, or comes in disguise.
His lilas or pastimes are so uncommon and amazing that people are still talking about them thousands and millions of years later and they are also impossible for anyone else to imitate.
The Bhagavad-gita ("song of God") is the famous conversation between the peerless warrior Arjuna and the Supreme Being, Krishna, who posed as Arjuna’s charioteer. The conversation took place at the onset of the battle of Kurukshetra, around 3200 B.C.
In the Bhagavad-gita, Krishna explains all the essential spiritual truths: the difference between the soul and the body, the difference between the soul and God, the science of reincarnation, the nature of time, the ultimate goal of yoga, why different kinds of religion appeal to different kinds of people, and the ultimate purpose of human life.
His mission each time He incarnates is to free the righteous from the bondage of temporary, material existence and to rid the world of villains. The Srimad-Bhagavatam describes many of Krishna’s incarnations. It also gives us a glimpse into Krishna Himself interacting with His devotees.
In his latest incarnation, He appeared as Lord Chaitanya in which He played the role of His own worshiper. He is the combined form of Krishna and Radha, Krishna's eternal consort and most dear devotee. He came to experience the love She feels for Him, and to show by example how to fully surrender to Krishna. He exhibited symptoms of love of God to the highest degree.