What is the effectual call in Christian theology?

In the context of the sermon, the effectual call is an integral part of God's plan for salvation. It is described as the moment when the Holy Spirit actively changes a person's heart, transforming a general call into a powerful, saving invitation that leads to faith. Unlike the general call that may fall on deaf ears, the effectual call brings forth immediate responses, akin to when Jesus called Lazarus from the dead. This divine calling not only invites but guarantees that those selected will respond and be saved.