How do we know God's promises are certain?

The sermon highlights that God's promises, as seen in Joshua 6:2, are stated in the past tense, indicating that they are already accomplished despite human circumstances. The certainty of God's promises stems from His sovereignty and unchanging nature; as seen in Romans 8:28-30, He works all things for the good of those He has called. Furthermore, God's track record of triumph throughout biblical history—through actions like the deliverance from Egypt—provides believers with confidence that what He has promised will indeed come to pass.