As the mountains surround Jerusalem, so the LORD surrounds his people, both now and forevermore.

Psalms 125:2

Mountains are the best fort for city. It is the best defense and protection. Many famous ancient cities were built on top of the mountains.
It becomes difficult for the enemy to launch its attack. Mountain serves as a self-defense.
Jerusalem was one such city which was surrounded by mountains; hence it was the most difficult city to be captured.
The psalmist applies this practical principle to our spiritual life and mentions a truth for us. The truth is the LORD surrounds us as the mountains surround Jerusalem.
Which means LORD is our defense from every attack of the enemy.
When Satan accuses us every time, the LORD comes to our defense and intercedes for us. He always presents us blameless because we are washed by His blood.
That is why, even though we are weak and vulnerable, we are yet unconquerable because of the LORD's defense.
Today, you are surrounded by the LORD on every side. No weapons formed against you prosper because the LORD is on your side, and He protects you and is a defense for you.
You may see a storm rising against you, people rising against you, situation forming against you, don't be afraid, the LORD has surrounded you and will guard you and will not allow the weapon to form against you.
You are truly surround by the LORD Almighty.