When you begin Zephaniah you see nothing but condemnation of Israel. And, that condemnation continues through chapter three, down through verse seven.
But, the tone changes in verse eight.
8 Therefore wait ye for me, saith Jehovah, until the day that I rise up to the prey; for my determination is to gather the nations, that I may assemble the kingdoms, to pour upon them mine indignation, even all my fierce anger; for all the earth shall be devoured with the fire of my jealousy.
God is going to assemble the gentiles and judge them. And, when He does that…
9 For then will I turn to the peoples of a pure language, that they may all call upon the name of Jehovah, to serve him with one consent.
… a people of a pure language will call on the name of the Lord.
Unfortunately, I’m not really sure that you can say that Hebrew is this pure language. As a Hebrew speaker myself, I can tell you that there is much about Hebrew that is no longer ‘pure’ – if it ever was a pure language.
Even the characters that make up the Aleph-Bet aren’t the original characters that Moses would have known.
What is this ‘pure language’?
Well, I just said that Hebrew is not a pure language, yet it is clear to me that the Lord is speaking of Israel here. So, if Israel doesn’t speak a pure language, maybe her language is pure enough for God to call upon them.
10 From beyond the rivers of Ethiopia my suppliants, even the daughter of my dispersed, shall bring mine offering.
And yes, the Jews of Ethiopia have come from beyond the rivers of Ethiopia.
11 In that day shalt thou not be put to shame for all thy doings, wherein thou hast transgressed against me; for then I will take away out of the midst of thee thy proudly exulting ones, and thou shalt no more be haughty in my holy mountain.
12 But I will leave in the midst of thee an afflicted and poor people, and they shall take refuge in the name of Jehovah.
13 The remnant of Israel shall not do iniquity, nor speak lies; neither shall a deceitful tongue be found in their mouth; for they shall feed and lie down, and none shall make them afraid.
God will bring peace to Israel…
14 Sing, O daughter of Zion; shout, O Israel; be glad and rejoice with all the heart, O daughter of Jerusalem.
15 Jehovah hath taken away thy judgments, he hath cast out thine enemy: the King of Israel, even Jehovah, is in the midst of thee; thou shalt not fear evil any more.
16 In that day it shall be said to Jerusalem, Fear thou not; O Zion, let not thy hands be slack.
17 Jehovah thy God is in the midst of thee, a mighty one who will save; he will rejoice over thee with joy; he will rest in his love; he will joy over thee with singing.
18 I will gather them that sorrow for the solemn assembly, who were of thee; to whom the burden upon her was a reproach.
19 Behold, at that time I will deal with all them that afflict thee; and I will save that which is lame, and gather that which was driven away; and I will make them a praise and a name, whose shame hath been in all the earth.
20 At that time will I bring you in, and at that time will I gather you; for I will make you a name and a praise among all the peoples of the earth, when I bring back your captivity before your eyes, saith Jehovah.
… and all Israel will be saved!