Zechariah encourages the temple builders with a series of eight night visions and oracles, all pointing forward to the coming King who will enter Jerusalem on a donkey and be "pierced" for his people. It is one of the most messianic books in the Old Testament.
“Not by might, nor by power, but by my spirit, saith the LORD of hosts.”
“Rejoice greatly, O daughter of Zion… behold, thy King cometh unto thee: he is just, and having salvation; lowly, and riding upon an ass.”
“And they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son.”