Jesus was the root of David as well as a direct descendant of David. Why didn’t or did the Sadduccees and Pharisees recognize that Joseph was a descendant of King David’s?

Answer:

They chose not to see it:  John 3:19 …that light is come into the world, and men loved darkness rather than light, because their deeds were evil.

Matthew 23:27  Woe unto you, scribes and Pharisees, hypocrites! for ye are like unto whited sepulchres, which indeed appear beautiful outward, but are within full of dead men’s bones, and of all uncleanness.

The fact is, they did know and were able to ascertain who Jesus was if they only wanted, and that is what is so scary! That is why this group of people alone were warned about the blasphemy of the Holy spirit and the unforgivable sin…the sin which has to do with knowing full well that Jesus Christ is Lord and still rejecting Him to maintain your own power and control.

Matthew 12:22-24  Then was brought unto him one possessed with a devil, blind, and dumb: and he healed him, insomuch that the blind and dumb both spake and saw. And all the people were amazed, and said, Is not this the son of David? But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils. Matthew 12:31  Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.

Good question.
Pastor Brad