Joel 2:4

Overview - Joel 2
He shews unto Zion the terribleness of God's judgment.
12 He exhorts to repentance;
15 prescribes a fast;
18 promises a blessing thereon.
21 He comforts Zion with present,
28 and future blessings.
Treasury of Scripture Knowledge

Joel 2:4  (King James Version)
The appearance of them is as the appearance of horses; and as horsemen, so shall they run.

Revelation 9:7