In addition to the outward general call to salvation, which is made to everyone who hears the Gospel, the Holy Spirit extends to the elect a special inward call that inevitably brings them to salvation. The external call (which is made to all without distinction) can be, and often is, rejected; whereas the internal call (which is made only to the elect) cannot be rejected; it always results in conversion. By means of this special call the Spirit irresistibly draws sinners to Christ. He is not limited in His work of applying salvation to man's will, nor is He dependent on man's cooperation for success. The Spirit graciously causes the elect sinner to cooperate, to believe, to repent, to come freely and willingly to Christ. God's grace, therefore, is invincible; it never fails to result in the salvation of those to whom it is extended.
H. Wayne House