What does Romans 13:13-14 mean by "behave decently, as in the daytime"? In Romans 13:13-14 NIV we read

Let us behave decently, as in the daytime, not in carousing and drunkenness, not in sexual immorality and debauchery, not in dissension and jealousy.
Rather, clothe yourselves with the Lord Jesus Christ, and do not think about how to gratify the desires of the flesh.

People sin in daytime as well as night-time, so in what sense is &quot;daytime&quot; being used here?
Jesus and others in the Bible have used day and night figuratively. In general, light and day refer to positive aspects of a believer's relationship with God while darkness and night refer to more sinful aspects. 

For instance, in John 3:19-21, we read, 


  19 This is the verdict: Light has come into the world, but people
  loved darkness instead of light because their deeds were evil. 20
  Everyone who does evil hates the light, and will not come into the
  light for fear that their deeds will be exposed. 21 But whoever lives
  by the truth comes into the light, so that it may be seen plainly that
  what they have done has been done in the sight of God.


The light in this case is God sending Jesus into the world to save us, and especially to make us aware of that need. The darkness here is that part within us that prefers to hide from God's truth about our sinful state rather than have our sins exposed and forgiven. But "whoever lives by the truth," that is, he who is honest with himself about his shortcomings and recognizes the need for God's remedy, comes to the light -- comes to the need for faith in Jesus and forgiveness. 

Darkness refers to the "shady dealings" of mankind, where people will do what's wrong secretly in order not to be found out and accused. Being people "of the day" (1 Thess. 5:5) means to be bold and open in one's conduct, unafraid because it is right and honest and good.