Why did the House of David not lose the kingdom altogether?

Answer 1

The Bible tells us that the fr more numerous northern tribes broke away from the united monarchy of Israel, and somehow managed to be called 'Israel' while the smaller and less prosperous remnant enclave, having been deprived of that honour, took the name 'Judah'. This supposedly happened because Solomon's son and successor, Rehoboam, insisted on continuing his father's unwise policy of swingeing taxes on the people. While this seems to have caused such hardship among the Israelites as to lead to their revolt, there is no suggestion that the people of Judah had suffered or were ill-disposed towards the House of David.

If the biblical account seems improbable it may be because, as most historians now believe, there was no united monarchy of Israel. Israel Finkelstein says that the two nations were always separate and had their own, different culture, different pottery styles and different dialects of the Hebrew language. It is considered likely that David and Solomon were only local warlords and that the first hereditary kings of Judah did not live until centuries after the time of Rehoboam.

Answer 2

The tribes of Judah and of Benjamin were retained to David's kingdom to fulfil God's promise and the prophecy that the Law-giver, that is Christ would come from the tribe of Judah.