The abstract noun "faithfulness" can be stated as "faithful" or "loyal." See how you translated a similar phrase in [Ezra 7:28](../07/28.md). Alternate translation: "he has been faithful to us" or "he has been kind to us" (See: [[rc://en/ta/man/jit/figs-abstractnouns]])
The king could not literally see the temple, but he did know about what was happening in Jerusalem. Here "sight" is a metonym for what a person knows. Alternate translation: "so that the king of Persia knows about it" (See: [[rc://en/ta/man/jit/figs-metonymy]])
Possible meanings are 1) the wall of safety is a wall to protect the people. Alternate translation: "he has given us a wall to protect us" or 2) this is a metaphor for Yahweh protecting his people. Alterate trasnslation: "he protects us like a wall" or "he gives us protection" (See: [[rc://en/ta/man/jit/figs-metaphor]])