The Day of the Lord is God’s wrath on the whole earth.  It will come. 

“Be silent before the Sovereign Lord, for the day of the Lord is near.”  Zephaniah 1:7.  

Many choose to ignore this fact because they do not want to recognize that God will bring Judgement on the wicked.  Now, who are the wicked?  The wicked are those who reject God.

“In his pride the wicked man does not seek Him; in all his thoughts there is no room for God” Psalm 10:4

However, those who seek the Lord, righteousness, and humility will be hidden in the day of the Lord.

“Seek the Lord, all you meek of the earth, Who have upheld His justice. Seek righteousness, seek humility. It may be that you will be hidden In the day of the Lord’s anger.” Zephaniah 2:3