F. F. Bruce wrote that the "effectual calling which is the work of God's Spirit, whereby, convincing us of our sin and misery, enlightening our minds in the knowledge of Christ, and renewing our wills, he doth persuade and enable us to embrace Jesus Christ, freely offered to us in the gospel."
The effectual call to Christ is by the Holy Spirit through the gospel. It is the Holy Spirit's work to convince us to believe and receive Christ. Jesus said, "And when he has come, he will convict the world of sin, and of righteousness, and of judgment; of sin because they do not believe in me" (John 16:8-9).
Bruce noted from Scripture that the called of God belong to Jesus Christ (Romans 1:6); called to be saints (Romans 1:7), because of his call (Romans 9:11). The Holy Spirit calls us to Christ through the gospel.
Dr. Bruce recognized that the call to Christ is offered freely to all. However, he focused upon those who respond to the gospel of Christ in the effectual call. The convincing work of the Holy Spirit makes the difference in those who come to Jesus Christ our Lord by faith.
The effectual call to Christ is not received by those who refuse in unbelief. Therefore, they must be responsible for their own just condemnation. Dr. Bruce explained "that the gates of God's mercy stand wide open for their entrance, that his free pardon is assured in Christ to all who claim it by faith."