Despite man's unfaithfulness and despite the Lord's anger, there is yet hope. Reading these verses we see that we are told to sing and rejoice.
This is because after the Lord's day of wrath, there is a recalling of the remnant of the faithful. Those who have been faithful will survive the day of judgment and will be found victorious.
The Lord says He will purify the lips of the peoples. that all of them may call upon His name. This reminds us of the picture of Isaiah.
Remember when he found himself in the throne room of God, with all the angels. The glory of the Lord was so heavy that he fell on his face saying "woe is me for I am a man of unclean lips." And an angel took a coal from the altar and touched his lips to purify them. Then he was worthy to speak the name of the Lord as an emissary of God.
Here too, God says He will purify the lips of the people. Those of us who are faithful to God should rejoice in this passage. It means that we will speak the righteousness of God to the nation. We are to be His emissaries in this hurting world. It is our duty and our privilege to speak for the righteousness of God, the love of God, the mercy of God and the wrath of God in equal proportion.
It is only when we tell the whole truth of God that we can be rightfully called His emissaries.
Open our ears and hearts to learn of You. Purify our lips to tell of You. Send us wherever You wish to spread the good news to all people. Soften our hearts to love all Your children.
In Jesus' most precious name.