The central message of this sermon is that faith is being sure and certain of what we hope for and cannot see. Faith is not just a feeling or an attitude, but rather it connects us to the promises and certainties of God, which are yet unrealized in our lives. The speaker argues that biblical hope is not about wishful thinking or uncertainty, but rather about accessing the objective reality of God's promises through faith. This means that we can be confident in the things that are not yet visible or tangible in our lives, such as the forgiveness of our sins or the glorification of our bodies in heaven. The speaker emphasizes that faith is like a plug-in that connects us to the power and promises of God, making them real and present in our lives. This understanding advances the belief that faith is not just a passive acceptance of uncertain possibilities, but rather an active trust in the certainties of God's Word. The takeaway for listeners is that they should cultivate a sure and certain faith in God's promises, which will bring meaning, comfort, and significance to their lives even in the midst of uncertainty and imperfection.