Jesus’ self-description follows directly on his statement that the book of Revelation is his work. So Jesus’ self-description colours the value of this revelation (and vice versa).
David
was the central king in Old Testament Israel, the founder of the dynasty from which Christ Jesus was born. To claim an identity as root…of David
is to say that David’s origin and nourishment lay in Jesus Christ—and hence Jesus predates David (John 8:58). To claim an identity as descendant of David
is to say the inverse, namely, that Christ is the fruit that grew on the tree of David—and so postdates him. These two statements are not mutually exclusive but point up the Speaker’s supremacy over the royal house of David such that he can be root and fruit at the same time—and hence the greater David.
Jesus’ self-designation as the root…of David
echoes the words of the elder in response to John’s despair when none could be found who could open the scroll in God’s hand (Revelation 5:5). Such was the Lamb’s supremacy that he long ago produced (the house of) David—and so was in a position to take that scroll from God’s hand, open its seals, and make happen all that God had ordained should happen. So the designation root of David
forms bookends to the section of the book of Revelation describing the spread of the gospel over all the earth, human response to the gospel, and God’s response in turn to the rejection of the gospel, that is, his revelation of what is to happen in the new dispensation.
16 “I, Jesus, have sent my angel to testify to you about these things for the churches. I am the root and the descendant of David, the bright morning star.”