Encyclopedia of Mormonism, pg. 405; “The Doctrine and Covenants is a compilation of revelations, most of which were received by the Prophet Joseph Smith for the establishment and governance of the kingdom of God in the latter days. It is a standard work of the Church…Its main focus is to build up the Church of Jesus Christ and to bring people into harmony with Christ’s kingdom. It is viewed as the capstone of the Church; its companion volume, the Book of Mormon, is seen as the keystone (Benson, pp. 83-85).”
Is. 59:21; “As for me, this is my covenant with them, saith the LORD; My spirit that is upon thee, and my words which I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed’s seed, saith the LORD, from henceforth and for ever.”
The Bible doesn’t need any help. It already points to Jesus and His kingdom and builds up the church. If the D&C is the capstone of the Church and the Book of Mormon is the cornerstone o the Church, who is Jesus?