What does 'effectual calling' mean in Reformed theology?

In Reformed theology, effectual calling is the work of the Holy Spirit whereby He effectively draws the elect to faith in Christ. This is distinct from the outward call of the gospel that is made to all; the effectual call ensures that those who are chosen by God will respond positively. As demonstrated in Genesis 24:57-58, Rebecca's willing response to the call signifies how God operates through His Spirit to prepare the hearts of His people. The New Testament supports this through passages like John 6:37, where Jesus states, "All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out." This reveals that the call to salvation is not only an invitation but a divine summons that results in true faith and repentance.