The central message of this sermon is that unity in the church is not just a desirable trait, but a vital necessity, and it can only be achieved through a common purpose and the empowerment of the Holy Spirit. The early church's remarkable unity was not a superficial or external imposition, but a natural outworking of their transformed lives, changed by the grace of God. This unity is reflected both spiritually and materially, as believers shared their possessions and resources in common. The sermon emphasizes that this kind of unity is not just about being "nice" to each other, but rather about having a deep-seated commitment to a common goal, which is to spread the message of Christ's resurrection. Through this lens, the speaker encourages listeners to recognize that true Christian living involves more than just individualistic efforts, but rather a reliance on God's grace to empower and sustain us in our walk with Him.