BS refers to Heavenly Parents.
Barbara Smith, "A Season of Strength," October 1983 General Conference Address (Women's Session) in Ensign (November 1983), accessed July 27, 2021
In the beloved Latter-day Saint hymn ‘O My Father,’ Eliza R. Snow celebrates in words the continuity of family relationships beyond death and reminds us of a glorious reunion with our heavenly parents. Written as solace to a dear friend, Zina Huntington, who had lost her mother and father in tragic deaths, the well-known lines of this hymn give poetic statement to a great truth revealed through the Prophet Joseph Smith.