en_tn_condensed/isa/39/04.md

They have seen everything in my house. There is nothing among my valuable things that I have not shown them

These two sentences mean the same thing and are used together to emphasize how much Hezekiah showed the men. (See: rc://en/ta/man/translate/figs-parallelism)

everything in my house

This is a generalization, as Hezekiah showed them many things, but not necessarily everything in the palace. Alternate translation: "almost everything in my house" (See: rc://en/ta/man/translate/figs-hyperbole)

There is nothing among my valuable things that I have not shown them

This can be expressed positively. Alternate translation: "I showed them all the valuable things in my palace" (See: rc://en/ta/man/translate/figs-doublenegatives)