Jesus was a descendant of David (Jeremiah 23:5-8; Matthew 1:1,6).
Jesus does not come from the line of David since Joseph is not the biological father of Jesus. If one believes that Jesus was born of a virgin then he had no tribal lineage since (1) God is not of any tribe and (2) the tribal lineage is passed on exclusively through the biological father (Numbers 1:18, 36:7).
There will be a new set of laws, a new contract, with man (Jeremiah 31:30).
The “new” covenant is described beginning in verse 32. The covenant that Christianity speaks about (“New Testament”) is nowhere to be found within this description.
There are two Messianic prophecies attached to this “new” covenant that have yet to be fulfilled (Jeremiah 31:33, 37-39).