How do we know the concept of heaven is true?

Heaven, as depicted in Bunyan's description of the Celestial City, is grounded in biblical truths such as those found in Revelation 21:21, which describes the city built of precious materials, revealing its splendor. Christians hold that heaven is not only a future hope but also a present reality in the relationship with Christ, as seen in John 14:2-3 where Jesus promises a place for His followers. The longsuffering and desires of the faithful in Bunyan's allegory reflect the deep-seated hope for the eternal communion with God that awaits them in heaven.