Following are a number of back-translations of Romans 3:4:

• Uma: “Even though all men lie, God’s words are still true. Like King Daud long ago said: ‘O Lord, your (sing.) words are indeed true. No matter who criticizes you (sing.), they must admit that you (sing.) are upright.'” (Source: Uma Back Translation)
• Yakan: “Even if all human beings are liars yet God does not lie. Whatever he says he will really fulfill (it). It is written in the holy-book about this, it says, ‘Whatever you speak, God, is really true, that’s why it is known that you are straight. And when/if one faults you/accuses you of fault finally it is known that you have no sin/fault.'” (Source: Yakan Back Translation)
• Western Bukidnon Manobo: “For even though all mankind are liars, by contrast everything that God says is true. For there is a written word of King David long ago in which he testified about the righteousness of God. He says, ‘It’s not possible that your arguments are not true, for if you are accused your arguments will always win the case,’ said David.” (Source: Western Bukidnon Manobo Back Translation)
• Kankanaey: “No indeed! Because even if all people tell-lies, it is absolutely not possible that God would tell-a-lie. Consider the written word of God which says, ‘When you (sing.) speak, God, it becomes-known that what you (sing.) are saying is exactly correct. If moreover there is someone who accuses you (sing.), it is not possible that you (sing.) will be defeated.'” (Source: Kankanaey Back Translation)
• Tenango Otomi: “No, not that. Although if all the people are liars, yet God never lies. The word written in the Holy Book says: ‘You my God, it is apparent that concerning the word you speak, it all is good. No person will come forth who can say that the word you speak is not right’, it says.” (Source: Tenango Otomi Back Translation)

For the Old Testament quote, see Psalm 51:4