(An overview from Genesis to Revelation by selected passages.)
The word of the LORD that came to Joel, the son of Pethuel:
Blow a trumpet in Zion;
sound an alarm on my holy mountain!
Let all the inhabitants of the land tremble,
for the day of the LORD is coming; it is near,
a day of darkness and gloom,
a day of clouds and thick darkness!
Like blackness there is spread upon the mountains
a great and powerful people;
their like has never been before,
nor will be again after them
through the years of all generations.
The LORD utters his voice
before his army,
for his camp is exceedingly great;
he who executes his word is powerful.
For the day of the LORD is great and very awesome;
who can endure it?
Joel 1:1; 2:1-2,11 (ESV)