king.

Daniel 3:4, 5
Then the herald loudly proclaimed, "O peoples, nations, and men of every language, this is what you are commanded: . . .

O King.

Daniel 2:4
Then the astrologers answered the king in Aramaic, "O king, may you live forever! Tell your servants the dream, and we will give the interpretation."

Daniel 5:10
Hearing the outcry of the king and his nobles, the queen entered the banquet hall. "O king, may you live forever, " she said. "Do not let your thoughts terrify you, or your face grow pale.

Daniel 6:6, 21
So the administrators and satraps went together to the king and said, "O King Darius, may you live forever! . . .

Romans 13:7
Pay everyone what you owe him: taxes to whom taxes are due, revenue to whom revenue is due, respect to whom respect is due, honor to whom honor is due.