3:18 In the past Jews who lived far from Jerusalem were very sad because they could not travel to Jerusalem to observe Israel's annual feasts. They suffered a certain criticism from their fellow Jews for living far away from Jerusalem. But in this time of blessing (the Millennium) the Lord will enable them to come to Jerusalem to celebrate the feasts.29
3:19-20 Having dealt with the Jews' oppressors (cf. vv. 8-15; 2:4-15; Gen. 12:3), the Lord will deliver even the weak and dispersed of His people and give them a worldwide reputation for goodness (cf. Deut. 26:19). He will regather them in their land and give them a good reputation when He restores their fortunes (cf. v. 15; Gen. 12:1-7; 13:14-17; 15:7-21; 17:7-8; 2 Sam. 7:16; Ps. 89:3-4; Isa. 9:6-7; Dan. 7:27).
Zephaniah concluded his book by affirming that such was Yahweh's declaration. He would indeed restore His people.
Eight times in verses 18-20, in the NASB, the Lord said, "I will,""I am going to,"or "When I."The future restoration and blessing of Israel in the world will be something that Yahweh Himself will accomplish "in that day"(i.e., the day of the LORD"). No one but He could ever accomplish it, and no one but He would.