The central message of this sermon is that when Jesus is referred to as "the Son of God," it means he is literally God, not just a unique relationship or status with God. The speaker argues that this understanding stems from the Hebrew idiom "son of X" in the Old Testament, where "son of" often conveys an idiomatic meaning rather than a literal one, indicating identity, character, or affiliation. This idiom is pervasive throughout the Hebrew Bible and also appears in various forms in the New Testament. By examining this idiom, the speaker aims to convey that Jesus' divinity is not just a theological concept but a fundamental truth about who he is. The takeaway from this sermon is that understanding Jesus as the Son of God means recognizing him as fully divine, not just a special relationship with God.