I am 0.6% Ashkenazi Jewish from the tribe of Levi found from an Ancestry DNA test my sister took.
When studying the history of the twelve tribes of Israel being the sons of Jacob/Israel we find from 1047 B.C. and 931 B.C. the twelve tribes were under the leadership of three Kings, Saul, David and Solomon. Near the end of Solomon's reign he fell into idolatry and God spoke of tearing apart the Kingdom as judgment for these sins, 1 Kings 11:10-12.
After Solomon's death his son Rehoboam became King and those ten Northern tribes (Israel/Ephraim) rebelled against King Rehoboam and followed after Jeroboam up North causing a division of the north and south Kingdom. Only the tribe of Judah (Judah) and the tribe of Benjamin (Judah) stayed Loyal to King Rehoboam in the southern Kingdom for they kept Gods commandments as they knew David was the lineage of the promised Messiah as it was prophesied of the prophets of God. For almost two centuries the two Kingdoms where divided, but a remnant of the ten tribes soon came back to Judah after following Jeroboam as he turned the northern Kingdom into idol worshipers.
This is the importance of the 144,000 of the house of Israel and their generations unto the end of days. There were those of the old covenant that were faithful to God in keeping all his commandments and repented of their idol worshipping. Their generations who have also come back to Gods grace that are still alive during the seven trumpet sounds will continue to preach to the Jews as it was with the twelve disciples in Matthew 10:6. The generations of the 144,000 that are still alive have the seal of God on them which are the seven Spirits of God as they will have to endure much persecution until the end of days before the return of Jesus.
(Seven Spirits of God are found in Isaiah 11:2 and mentioned in Rev 1:4.
Spirit of the Lord, wisdom, understanding, counsel, power, knowledge and fear/respect of the Lord.)