Surah 47:4

Killed millions of….? Who did they kill?

The Messiah is supposed to be from the line of David. The new Testament has a geneology that leads up to Joseph. When Joseph is about to pass his Davidic genes to his son, the Holy Spirit comes in and does it for him. It was not Joseph’s sperm. Jesus was literally not from the line of David according to this perspective.
Jesus was not a military leader who would rescue the jews from Roman rule. He was pro-roman (give to caesar what belongs to caesar)

The Jews’ idea of the Messiah is faulty. As a result they missed out experiencing Jesus as their Messiah because He hid himself so well in simplicity. That’s the same problem with human beings today. You want to “arrange” God based on your human understanding of how He should act instead of saying “God, You are the Potter I am the clay. Mould me according to thy Will.” The Jews just like people today want to control God according to their limited human understanding.
Jesus fulfilled every single Messianic rule to the letter, from birth to death. His mission at the time was to reconcile humanity back to God whereas the Jews wrongly believed that He was coming to set them free from Roman occupation. When Jesus comes back to live on earth the second time, He will be that Great King and ruler the Jews had in mind. Indeed, Jesus will rule side by side with king David in Jerusalem during the millennium.

If Jesus the Messiah was the literal seed of David, why did He deny it?

Matthew 22:41-46. While the Pharisees were gathered together, Jesus asked them, “What do you think about the Messiah? Whose son is he?”

“The son of David,” they replied.

He said to them, “How is it then that David, speaking by the Spirit, calls him ‘Lord’? For he says, ‘The Lord said to my Lord: “Sit at my right hand until I put your enemies under your feet.”’ If then David calls him ‘Lord,’ how can he be his son?” No one could say a word in reply, and from that day on no one dared to ask him any more questions.

This means there is no firm Biblical basis for the belief that Jesus was genetically descended from David. The Bible establishes only that his adoptive father Joseph was a descendant of David.