text: why do they trace joseph's bloodline as proof that jesus was of the house of david and adam? the bible spends many words tracing joseph's bloodline back to david and to adam.   considering that jesus was born of mary via the holy ghost.  joseph's blood is not in jesus.  and that creates my question.  if joseph's blood is not in jesus then tracing joseph back to david and to adam doesn't make jesus related to david or adam.  mary's blood would be in jesus so tracing her bloodline would seem reasonable.  but the bible traces joseph's.  why? part of the prophecy of jesus christ was that he must be of the lineage of david, "the root of jesse" (jesse being the father of king david.)  although not a single drop of blood from joseph flows in the body of jesus.  (it's from the males that the "sinful nature" is passed down) and the mother's blood never mixes with the unborn child. (that's why they have paternity tests)  the lineage of jesus is prophisied to be from the lineage of kings.  if you read the lineage in the gospel of matthew it is traditionally known to be that of joseph, but the lineage of jesus in the gospel of luke traces the ancestroy of mary (not joseph).  so either way you go, the lineage goes back to king david.  thereby fulfilling the prophecy of his lineage from both parents. the prophecy of descending from king david and the prophecy of the blood lineage.     two prophecies out of 435 fulfilled with one set of parents!!!