Part 56 of the David Pawson 'Unlocking the Bible' Podcast series 
While some prophets had a lifetime of prophesying, David Pawson says that Haggai spoke for only 3 months. He came after the exile, so his job was to encourage Jews who had returned. Not all Jews returned to Israel as they had become established in Babylon. The returnees had problems because the land had not been cultivated for 70 years, the walls had been torn down, there was opposition from the Samaritans and financial support was withdrawn so this was heavy going for them. Haggai spoke to them 18 years after they had returned, and he provoked them to rethink their attitudes. They had stopped building the temple because money was short, but Haggai showed them that money was short because they had stopped putting God first. When they resumed the building, there was still a drought – because they had not put their lives right with God. They responded well and Haggai encouraged them to be strong and not afraid. And eventually financial support came to them from Persia again. Haggai gave them a promise from God that His glory would fill the temple.