Albert Barnes Commentary 2 Chronicles 14:7

"For he said unto Judah, Let us build these cities, and make about them walls, and towers, gates, and bars; the land is yet before us, because we have sought Jehovah our God; we have sought him, and he hath given us rest on every side. So they built and prospered." — 2 Chronicles 14:7 (ASV)

The land is still before us—that is, it is "unoccupied by an enemy" and "open for us to go wherever we please." Compare Genesis 13:9. The fortification of the strongholds would be an act of rebellion against Egypt, and it might be expected that the Egyptians would endeavor to put a stop to it.