Ephesians 6:13-14
Therefore, put on the full armor of God, so that you can withstand [the devil, See verse 11] when the evil day comes. And, after you have done everything you can, still remain standing firm [in the faith].
1 Thessalonians 5:2
for you know perfectly well that the day of the Lord [i.e., when He returns, See II Thess. 2:1-2] will arrive like a thief coming in the night.
2 Peter 3:10
But the day of the Lord will come as a thief [i.e., unexpectedly]. At that time the heavens will pass away with a loud noise and the elements [Note: This refers either to the heavenly bodies or to the material components of the universe], will be dissolved with intense heat. And the earth and its works [i.e., its activities] will be burned up. [Note: Some translations render this phrase as it is in some ancient manuscripts, "will be disclosed," or "will be laid bare"].
Revelation 6:17
For the terrible day of their anger has come, and who will be able to survive it?"
Revelation 16:14
For they are spirits of demons, which perform [supernatural] signs. These spirits go out to the kings of the whole world to assemble them for battle on the great day of Almighty God.
Revelation 20:8-9
and he will [again] go out to deceive the nations which are [located] throughout the whole world --- Gog and Magog. [Note: Based on Eze. 35-40, it appears that these names are used here figuratively for all the forces of wickedness which are enemies of God]. Satan will assemble them together for battle, and they will be as numberless as the sand on the seashore.