Summary: This next section gives exhortation those of us who are living in Christ. Paul is not presenting new information, he is urging his readers to use the knowledge he has already given them. It would be natural for the readers to ask “When?” after Paul had ex
Purpose: To encourage believers to live in the light of Christ’s soon return.
INTRODUCTION: In the previous section of this book (4:13-18) Paul gave us information about those who are already dead in Christ. This next section gives exhortation those of us who are living in Christ. Paul is not presenting new information, he is urging his readers to use the knowledge he has already given them.
It would be natural for the readers to ask “When?” after Paul had explained about the coming of Christ in 4:13-18.
Vs.1-3 I. The Unsaved and the Second Coming
The fact of Christ’s return is certain, the exact time of Christ’s return is certain because God has appointed it, but we cannot know when it is simply because God has not told us.
What do we know about those who don’t have Jesus as their own savior?
Vs.1-2 A. Their fate is sealed
“TIMES (chronon, length of time) signifies the chronological periods which are to elapse before the Second Coming; while seasons EPOCHS (kairon, kind or quality of time) refers to the significant events, the pregnant opportunities that transpire during these epochs.” 
The phrase THE DAY OF THE LORD was well known among the Jews, but they always thought of it as a Gentile judgment only. The OT prophets corrected that thinking. Amos 5:18-20 18 Alas, you who are longing for the day of the Lord, For what purpose will the day of the Lord be to you? It will be darkness and not light; 19 As when a man flees from a lion And a bear meets him, Or goes home, leans his hand against the wall And a snake bites him. 20 Will not the day of the Lord be darkness instead of light, Even gloom with no brightness in it? (NAU) Joel 2:1 Blow a trumpet in Zion, And sound an alarm on My holy mountain! Let all the inhabitants of the land tremble, For the day of the Lord is coming; Surely it is near, (NAU)
“What is THE DAY OF THE LORD? The day is the time of God's righteous intervention in history, when he will exact his rightful due from mankind.” 
1. The time of their judgment is unknown “like a thief in the night”
Paul is clear that there is no way to know when the Lord will come back. Jesus had already said, Mark 13:32-33 32 “But of that day or hour no one knows, not even the angels in heaven, nor the Son, but the Father alone. 33 “Take heed, keep on the alert; for you do not know when the appointed time will come. (NAU)
Notice what Jesus said when the disciples wanted the know when the Lord was coming back: Acts 1:6-8 6 So when they had come together, they were asking Him, saying, “Lord, is it at this time You are restoring the kingdom to Israel?” 7 He said to them, “It is not for you to know times or epochs which the Father has fixed by His own authority; 8 but you will receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth.” (NAU)