Following are a number of back-translations of 1 John 5:10:

• Uma: “People who believe in God’s Child, they know in their hearts that God’s testimony is true. Whoever doesn’t believe God, they are actually calling-a-liar God, for they haven’t believed God’s testimony that talks about his Child.” (Source: Uma Back Translation)
• Yakan: “Whoever trusts in the Son of God, he knows in his liver that Isa is really God’s Son. But the one who doesn’t believe God, it is as if he says that God is lying because he does not believe the witness of God about his Son.” (Source: Yakan Back Translation)
• Western Bukidnon Manobo: “Anyone who believes that Jesus is the Son of God, he has become convinced by the witness of God. Anyone who will not believe in the witness of God, he thinks of God as a liar, for he has not believed the witness of God about his Son Jesus.” (Source: Western Bukidnon Manobo Back Translation)
• Kankanaey: “Whoever then believes in the Child of God, what God confirmed concerning him has been stored-away in his mind, but as for the one who doesn’t believe what God said, he turns-God -into a liar, because of course he doesn’t believe what he said.” (Source: Kankanaey Back Translation)
• Tagbanwa: “Therefore whoever believes-in/obeys and trusts the Son of God, he is sure in his mind/inner-being that this testimony of God is really true. But as for the one who doesn’t believe this testimony of God, he is doing none other than saying God is lying, because he isn’t believing what he is testifying concerning his Son.” (Source: Tagbanwa Back Translation)
• Tenango Otomi: “He who believes the Son of God already knows in his own heart that what he believes is true. He who does not believe what God says, this person calls God a liar because he does not believe the word God has said about who his Son is.” (Source: Tenango Otomi Back Translation)
• Yatzachi Zapotec: “If we trust in God’s son, God speaks about his son in our head-hearts. If we do not believe God’s words, we treat God like a liar, because we do not believe his words which he speaks about his son.”
• Eastern Highland Otomi: “He who believes God’s Son, has been given understanding, and knows, himself, in his heart what is true. But he who doesn’t believe God, he looks on God as a liar, because he didn’t believe what God said about his Son.”
• Tzotzil: “If we believe the word of the Son of God, thus we know that it is true what God has told us about his Son. If we do not believe the word of God’s Son, we think wrongly that God lies because we do not believe what God has told us about his Son.”
• Candoshi-Shapra: “The one who rests-the-whole-weight of his heart on God’s Son has God’s telling in his own heart. The one who doesn’t say, ‘God is telling the truth’ makes God as-if-He-were-a-liar. For he doesn’t keep (believe) God’s telling, For he doesn’t say, ‘It’s true’ about what God says about His Son.”
• Yanesha’: “If any one believes in our Father’s Son, he has thus he knows by himself. The one who does not believe in our Father does toward him as if he were a deceiver, because he does not believe our Father, his causing-to-know with reference to his Son.”
• Aguaruna: “He who says ‘Jesus is truly God’s son,’ that one thinks the truth concerning what God tells, but he who does not believe this is like that one who says ‘God is a liar,’ because he does not believe what God told about his Son.” (Source for this and two above: Mildred Larson in Notes on Translation, July 1965, p. 1-15)
• Sayula Popoluca: “He who believes God’s Son, he knows that it is true that which God says. And he who doesn’t believe God, he says that God lies, because he doesn’t believe what God says so we can know his Son.” (Source for this and three above: John Beekman in Notes on Translation 12, November 1964, p. 1ff.)