Following are a number of back-translations of Romans 15:21:

• Uma: “I want to fulfill the words of the Holy Book that say: ‘People who have not yet been announced-to, they will know who he is. People who have not yet heard his news, they will hear and understand the news.'” (Source: Uma Back Translation)
• Yakan: “It is fulfilled already what has been written in the holy-book, saying, ‘The people who have not been told eventually will know about him. And the ones who have not been able to hear, they will understand about him.'” (Source: Yakan Back Translation)
• Western Bukidnon Manobo: “I have fulfilled the written word of God which says, ‘Those people who have not yet heard His name, they will know just the same who He is. And those who have not yet been told, there will be a time when they at last, will understand.'” (Source: Western Bukidnon Manobo Back Translation)
• Kankanaey: “What I have been doing is based on the written word of God which says, ‘Those who haven’t heard concerning him, they will see him and they will understand concerning him.'” (Source: Kankanaey Back Translation)
• Tenango Otomi: “I am doing like the word in the Holy Book says: ‘Those people who have never heard God’s word will hear. Those people who have never been told about it will be told.'” (Source: Tenango Otomi Back Translation)

For the Old Testament quote, see Isaiah 52:15