Chapter 1

Time stamped the 2nd year of Darius, 6th month, first day.  That would be Aug 29, 520 BC.  This is not Darius the Mede, this is Darius I Hystaspes, who followed Cambyses.  He is the great grandson of Cyrus the Great's Brother.  A prophecy for Zerubbabel and for Joshua - politics and religion.  The people say it is not yet time to build the temple.  Yet they live in nice houses while the temple is in ruins.  Then some questions well put in these verses:

5 Now, therefore, thus says the LORD of hosts: Consider your ways. 6 You have sown much, and harvested little. You eat, but you never have enough; you drink, but you never have your fill. You clothe yourselves, but no one is warm. And he who earns wages does so to put them into a bag with holes. [Hag 1:5-6 ESV]

Haggai says that they are making no real progress because they are out of God's will.  Same thing happens to us today.  Good one for FB.  Short and sweet. 

Through Haggai, God says that because they look to their own houses and neglect His, the dew and rain have stopped, and so the harvest is much less.  The response from Zerubabbel and Joshua begins in vs 12.  They fear the Lord, both these two leaders and the people.  They listen.  They get to work on the temple.  This is a big change from the pre-exilic nation.  Finally, they are willing to listen, and to act.

This verse:

12 Then Zerubbabel the son of Shealtiel, and Joshua the son of Jehozadak, the high priest, with all the remnant of the people, obeyed the voice of the LORD their God, and the words of Haggai the prophet, as the LORD their God had sent him. And the people feared the LORD. [Hag 1:12 ESV]

At this point we are told that there is still a high priest in Judah.  The ancestry has been preserved, so that God and the people recognize Joshua as the high priest.  So following Babylon, the office of high priest continues, and we can believe that from there, it would have been preserved through the generations into the time of Christ.  Zerubbabel is referred to in vs 1 as the governor of Judah.  Not as Prince, and certainly not as King.

Note that God Himself stirred up Zerubbabel, Joshua, and "all the remnant" to get to work on the temple.  So it was not that they just decided.  It is that God wanted it built, and He put the willingness to do so right into them.