“prince.” The Messiah, Jesus Christ, is the prince, the Son of God the king (see commentary on Ezek. 44:3). He will have a land area set aside for himself in the Millennial Kingdom. Joshua, a type of Christ, foreshadowed this when he received a city in the Promised Land as his personal inheritance in return for his faithfulness to God (Josh. 19:49-50).
“to the east border of the land.” The east border of the land of Israel in the Millennial Kingdom will be the Jordan River.
“to the west border.” The west border is the Mediterranean Sea.
“the house.” The house of God, meaning the Temple, and the sanctuary, in the temple proper, in the middle of the holy area.
“will be in its middle.” That is, in the middle of the 25,000 cubit square holy area, not in the middle of the whole east-west strip of land. Jerusalem and the Temple are not “in the middle” or the land belonging to the prince, the Messiah. They are to the east of the middle of that whole section, and although the topography of the earth will be different in the Millennial Kingdom than it is now, there is no indication that the Temple Mount will shift to the west from its current position.