In section 67 and 70, the Saints were deciding whether or not they should publish Joseph Smith’s revelations into a book, the Book of Commandments (which later became the Doctrine & Covenants). The Lord told them to bear record that the revelations were true. He gives them stewardship over the revelations and commandments He had given them. That means they are to protect and take care of the revelations. 

In section 68, the Lord told the Elders to preach the gospel and baptize. He commanded parents to teach the gospel to their children, and that children can be baptized when they are eight years old. The Lord said that parents should “teach their children to pray, and walk uprightly before the Lord.”  Parents can teach their children the gospel using the scriptures, including the Doctrine & Covenants.