[Dallin H. Oaks]
"The inspiration identifying the need for a proclamation on the family came to the leadership of the Church over 23 years ago. It was a surprise to some who thought the doctrinal truths about marriage and the family were well understood without restatement. Nevertheless, we felt the confirmation and we went to work. Subjects were identified and discussed by members of the Quorum of the Twelve for nearly a year. Language was proposed, reviewed, and revised. Prayerfully we continually pleaded with the Lord for His inspiration on what we should say and how we should say it. We all learned "line upon line, precept upon precept," as the Lord has promised (D&C 98:12). [Image of Gordon B. Hinckley] During this revelatory process, a proposed text was presented to the First Presidency, who oversee and promulgate Church teachings and doctrine. After the Presidency made further changes, the proclamation on the family was announced by the President of the Church, Gordon B. Hinckley."
[Dallin H. Oaks, "The Plan and the Proclamation," Conference Report (October 2017); Mormonr (mormonr.org/sources)]