George F. Richards describes that during his baptism and confirmation he made a covenant to keep God's commandments by raising his right arm to the square.
George F. Richards, One Hundred Fifteenth Semiannual Conference of the Church of Jesus Christ of Latter-day Saints (Salt Lake City: The Church of Jesus Christ of Latter-day Saints, 1945), 129–34
When I was baptized, and confirmed a member of the Church of Jesus Christ of Latter-day Saints, I was required to raise my right arm to the square, and covenant before God, angels, and witnesses present, that I would henceforth keep the commandments of God, as fast as they should be made known unto me. This represents the nature of the covenant entered into, by every person who is baptized and confirmed a member of the Church of Jesus Christ of Latter-day Saint. It is frequently spoken of as the covenant made in the waters of baptism. The nature of this covenant should be explained to every applicant for baptism, and he should manifest a willing acceptance, before being baptized.