Following are a number of back-translations as well as a sample translation for translators of Proverbs 25:3:

• Kupsabiny: “There is no person who knows all things perfectly in heaven/up or here on earth, and there is no other who knows perfectly what the king thinks.” (Source: Kupsabiny Back Translation)
• Newari: “No one is able to know what is in the heart of a king.
  His thoughts [are] high as the heavens
  [and] deep as the ocean.” (Source: Newari Back Translation)
• Hiligaynon: “As the heights of heaven and the depths of the ground can- not -be-measured, the thinking of the kings can- not also -be-fathomed.” (Source: Hiligaynon Back Translation)
• Kankanaey: “Nobody can-know the thoughts/mind of a king, because it is high like the highness of the sky and like the innerness (i.e., depth under ground) of the earth.” (Source: Kankanaey Back Translation)
• English: “It is not possible for anyone to measure how high the sky is or how deep the earth/ocean is;
  likewise , it is not possible for us to know all that kings are thinking.” (Source: Translation for Translators)