What is the significance of the strong city mentioned in Isaiah?

The strong city mentioned in Isaiah symbolizes the security, refuge, and protection that God provides for His people through Christ. Historically, cities with fortified walls were places of safety during times of attack. Isaiah 26:1 declares, 'We have a strong city,' reminding believers that their security lies not in their own strength but in God's appointed salvation. This strong city is established by God's own hand and represents the eternal protection afforded to those who are in Christ. The sermon emphasizes that just as a physical city provides safety from dangers, the strong city of God offers spiritual refuge from sin and the trials of life, ensuring that His elect are secured by His grace.