Haggai’s message is about how the truth about the future should inspire and disturb priorities in the present.
It’s set late-ish in the Israelite’s story, after Babylon has smashed their land and culture, and Persia has taken over Babylon’s Empire with a more reasonable approach of letting the Israelites resettle Jerusalem and re-establish their religion.
Haggai is a player in Nehemiah, the rebuilding of Jerusalem.
He tells the truth, based on revelation of God in the scriptures from the past: the people are rebuilding their houses and not the temple. It’s a call to reversal of their beliefs, but just re-occupation of their homeland.
Then when they are hypocritical, he tells a parable based on Levitical infection laws, saying their greedy morality will infect the house of God, and that rather the task wild infect then to revisit their own standards.
They are disappointed at the size of the new temple compared to the grandeur of Solomon’s. Again he turns to scripture, but this time to point to the future, the revelation of the Messiah and the covenant, that their temple and their Pele would be the Salvation of the world, God’s blessing poured out.
Trust his word. Obey. Don’t worry that what you are doing seems pathetic, God uses love for him, sincere faithful responses to the moment, in ways we can’t imagine.
Use what you know of God to make your contriburion to making the moment match what he has promised the future will be like.