Kabir Sahib was the first ever Sant Satguru. The Supreme Lord created Kabir Sahib by churning himself, so Kabir Sahib was nothing else but the essence of the Supreme Lord himself. He did not have a physical body like us human beings - he was pure consciousness which was beyond mind and body. Kabir Sahib descended on the earth in the guise of a human being on the full moon day in month of June (Poornima of Jyeshta Month) in the year 1398 at Lahartara Talaab (a pond) in Kashi.
At Lahartara Talaab, a bright white light from the sky descended on a lotus flower and took the form of a baby boy. At that time Ashtanandji (Disciple of Swami Ramanandji) was meditating near the pond. Ashtanandji was very astonished and reported the whole incident to his Guru- Swami Ramanandji. Hearing about the incident, Swami Ramanandji said that the world will soon come to know about this baby boy and he truly became well renowned in the world by the name "Sant Samrat Satguru Kabir Sahib" Kabir Sahib arrived on earth to preach the path of Satya Bhakti i.e. devotion to the Supreme Lord among the people and to awaken the souls so that they can attain true Nirvana from this worldly ocean instead of being reborn as one of the 84 lakh living beings.
For 120 years, He cautioned against popular myths that were prevalent in all religions and preached that Nirvana cannot be attained without getting the holy Name (Saar Naam) from a true Satguru himself. Kabir Sahib disclosed all the secrets of so called "God" of the Universe, who is no one else but the Formless Mind (Nirakaar Mann / Niranjan / Kaal Purush). He explained that all religions are worshiping the same "Formless God" in one way or the other i.e. Sargun in form of idol worship and Nirgun (formless) using 5 Yogic postures. He also gave the secret of Amarlok (4th Lok / Immortal Abode of the Supreme Lord) to the humanity, which is beyond the three worlds we know i.e. the heaven, the hell and the earth (Trilok). His teachings upset many spiritual leaders and they turned his arch rivals. He was punished with 52 death sentences also known as "Bawan Kasni" but he came out unscathed everytime. To denounce him they spread lies about him. Some described Him as the offspring of an unmarried Brahman girl; others said that he was married to Loi and had a son and a daughter- Kamal and Kamali when in reality He didn’t even have a physical body.
He proved this even in his death. In the year 1518 at Maghar, Kabir Sahib declared that he would depart from the world on Maagh Sudhi Ekadshi (An auspicious day falling on the next day of Lohri festival in Jan). General public along with devotees of Kabir Sahib gathered at Maghar on the date of His departure. Both Hindus and Muslims claimed His body but there was none when the cover over his dead body was lifted. Only lotus flowers were found which were shared by both communities and cremated them as per their own rituals. The following words were uttered at the time when Satguru Kabir Sahib left His body.