How do we know God's will is done in the preaching of the Gospel?

In the sermon, it is emphasized that while not every hearing of the Gospel results in salvation, God's sovereign will is always fulfilled when His Word is proclaimed. The Gospel is described as a two-edged sword, capable of softening some hearts while hardening others. Despite the sadness felt over individuals who reject the Gospel, believers rest in the assurance that God uses the preaching of the Gospel according to His divine purpose. This perspective reinforces confidence that God is sovereign over salvation and uses the proclamation of His Word to effect His purposes and bring glory to Himself.