The word "I" and the phrase "the king" refer to the same person. The king is reminding the people who hear this letter that he is the author of this letter.
# to inquire concerning Judah and Jerusalem according to God's law
What they were to inquire about can be stated more clearly. AT: "to investigate the situation in Judah and Jerusalem, in order to learn whether or not they are obeying God's law" (See: [[rc://en/ta/man/translate/figs-explicit]])
# You are to bring the silver and gold
Where they were to bring it can be stated clearly. AT: "You are to bring to Jerusalem the silver and gold" (See: [[rc://en/ta/man/translate/figs-explicit]])
# the silver and gold that they have freely offered
"Freely" means that they were not forced to offer the money. They gave it because they wanted to. AT: "the silver and gold that they have willingly offered"