41Now while the Pharisees were gathered together, Jesus asked them a question: 42“What do you think about the Christ, whose son is He?” They said to Him, “The son of David.” 43He said to them, “Then how does David in the Spirit call Him ‘Lord,’ saying,
44‘THE LORD SAID TO MY LORD,
“SIT AT MY RIGHT HAND,
UNTIL I PUT YOUR ENEMIES BENEATH YOUR FEET”’?
45“If David then calls Him ‘Lord,’ how is He his son?” 46No one was able to answer Him a word, nor did anyone dare from that day on to ask Him another question.
It's late here, but I don't think it is that Mary isn't His mother. Without reviewing it or looking it up and after a quick read I think it concerns His divinity, certainly looks like something concerning the father's side and perhaps the meaning of anointed, Christ, messiah being divine versus what they expected.
g'night and thanks for your post.