"...Jerusalem will be a city without walls...And I myself will be a wall of fire around it,' declares the LORD, 'and I will be its glory within." (Zech 2:4-5, NIV) "Some trust in chariots, and some in horses: but we will remember the name of the LORD our God" (Psa 20:7) Walls are an important part of a city in the pre-civilization era. During Bible times and some many years after, a city is only as strong and prosperous as its walls. In the Bible, we hear of the famous walls of Jericho (Josh 2:15), walls of Bashan (Deut 3:5,6), walls of Babylon (Jer 51:44), even Jerusalem as a city had a strong wall as was rebuilt by Nehemiah(3) and many others. Walls meant a lot to the people of a city so much that merchants, rich men will only choose to dwell and invest their money in cities where they are sure of its security and defence. These walls protected the people, and provided them a source of confidence. They could always point to their strong city wall and say, "We are truly safe inside here, nobody can harm us." But as strong as those walls were, it never takes time for armies to destroy them, invade those cities and cause great harm to the inhabitants. But we have a better wall. There is a stronger wall around Zion by which the inhabitants are kept safe..
God told the people of Israel through Zechariah, I will remove the physical walls around Jerusalem, and I will become a wall of fire around it. This was a prophecy which have been fulfilled in our time. Jerusalem here stands for the chosen people of God just like Jerusalem was the chosen city of God. Look at what the Bible says:
"But (now) you have come to Mount Zion, to the city of the living God, the heavenly Jerusalem. You have come to thousands upon thousands of angels in joyful assembly" (Heb 12:22)
We are a part of a new kind of Jerusalem, not the physical one; but the spiritual Jerusalem - the one of which Zechariah prophesied. And in this city, God Himself is our Defender. He is a wall of fire around us therefore no weapon fashioned against us shall ever propsper; and any tongue that rise against us in judgement shall be condemned (Isa 54:17) and He even said that "he that toucheth (us) toucheth the apple of His eye" (Zech 2:8)
I declare to you this morning, no matter whatever thing that come your way, God will defend you. He will arise as a wall of fire around you and everything you own - your life, your job, your business, your marriage, your children, your academics, everything about you is secured in Him. He said He will be your glory. That means He will help you excel and He will also keep you safe. You have absolutely nothing to be afraid of, God is your defender!