Building walls to protect our boundary is in the Bible.

Nehemiah rebuilds the walls of Jerusalem

Micah 7:11 The day for building your walls will come, the day for extending your boundaries.

Deuteronomy 3:5

All these were cities fortified with high walls, gates and bars, besides a great many unwalled towns.

Proverbs 25:28

Like a city that is broken into and without walls Is a man who has no control over his spirit.

Ezra 9:9

"For we are slaves; yet in our bondage our God has not forsaken us, but has extended lovingkindness to us in the sight of the kings of Persia, to give us reviving to raise up the house of our God, to restore its ruins and to give us a wall in Judah and Jerusalem.

Jeremiah 1:18

"Now behold, I have made you today as a fortified city and as a pillar of iron and as walls of bronze against the whole land, to the kings of Judah, to its princes, to its priests and to the people of the land.

Ezekiel 22:30

"I searched for a man among them who would build up the wall and stand in the gap before Me for the land, so that I would not destroy it; but I found no one.

Revelation 21:12-19

It had a great and high wall, with twelve gates, and at the gates twelve angels; and names were written on them, which are the names of the twelve tribes of the sons of Israel. There were three gates on the east and three gates on the north and three gates on the south and three gates on the west. And the wall of the city had twelve foundation stones, and on them were the twelve names of the twelve apostles of the Lamb.