The prophet Zephaniah was speaking to people who had experienced disruptions and disappointments. He promises them, "You don't have to be afraid anymore. God is right there, where you are, dwelling in your midst."
As Christians read these promises to ancient Jerusalem, we consider them extended to us. The Advent message is that God will love us, console us, and renew us.
We Christians need to appropriate not only the promise that God loves us but also appropriate the reminder that God is concerned about those that need some help. Verse 19 mentions specifically the lame and the outcast. We can start with those two groups specifically and continue by using the terms metaphorically.
God says, according to Zephaniah, "At that time I will bring you home (20)." I keep reading this trying to decide whether this home-bringing is after the lame are saved and the outcasts gathered or whether the promise is specifically to them.
And who are the outcasts for us anyway?