In the spring of 1820, Joseph went to a grove of trees near his home and knelt in prayer. He described his experience: “I saw a pillar of light exactly over my head, above the brightness of the sun, which descended gradually until it fell upon me… When the light rested upon me I saw two Personages, whose brightness and glory defy all description, standing above me in the air. One of them spake unto me, calling me by name and said, pointing to the other-This is My Beloved Son. Hear Him!” ( Joseph Smith-History 1:16-17 ).
Talk Source: http://mormon.org/joseph-smith