2 Corinthians chapter 12 gives an account of Paul being caught up into paradise, the new Jerusalem, which is a real city. Galatians 4:26 also mentions “the Jerusalem above,” hence it's clear that this is not referring to the church, but the city. Revelation chapters 21 and 22 state “these words are trustworthy and true” when mentioning the new Jerusalem. We know that new heavens and the new earth are real. Therefore, the new Jerusalem cannot be a mere symbolic expression. the new Jerusalem is a real city.