Midrasz do Aggeusza 2:3

...Another explanation. “Sing and rejoice, O daughter of Zion… And many nations shall join the Lord…” (Zechariah 2:14-15) R’ Chanina bar Papa said: this verse is only speaking of that hour when the Holy One judges the nations of the world in the time to come. In that hour the Holy One will bring all of the converts who converted in this world and judge the nations before them. He will say to them: why did you abandon Me and worship idols that have no substance. They will say before Him: Master of the World! If we had come to Your door You would not have accepted us. He will reply to them” let the converts who converted from amongst you and testify upon you. Immediately the Holy One will bring all the converts and they will judge them, saying before them: why did you abandon Him and worship idols that have no substance? Wasn’t Yitro an idolatrous priest? Since he came to the door of the Holy One, He received him. And were we not idol worshippers? Since we came to the door of the Holy One, He received us. Immediately all of the wicked will be ashamed due to the repentance of the converts. Judgement will be passed and they will pass from the world, as it says “But with one thing they are brutish and foolish, the vanities for which they will be punished are but wood.” (Jeremiah 10:8) Therefore it says ‘Sing and rejoice.’