The central message of this sermon is that the Bible's language about the "last hour" or "end times" often refers to a moment in history when Christ first came, rather than a future time period. The speaker argues that many Christians misunderstand this concept, thinking that it refers to a specific point in the future, whereas in fact, it is describing a critical juncture in time when God's presence was made manifest through Jesus' arrival. This understanding has significant implications for how we approach our relationship with God and the world around us, as it emphasizes the importance of living in light of Christ's presence and resisting the influence of antichristian forces that seek to undermine this relationship. The speaker wants listeners to understand that the concept of "last hour" is not just a future event, but rather a reminder of the significance of Jesus' first coming and its ongoing impact on our lives today.