Zechariah writes at the same time as Haggai and on the same subject: the rebuilding of the temple. God reminds them he had sent prophets to warn them of the destruction of Jerusalem, but he had also promised them a great future. Despite all they had experienced, God still intended to do all he said.
God鈥檚 promises to us are not based on us, but on God. Since God is God, we can depend on him regardless of our circumstances.