'The application to our lives is quite evident: if God gives anyone a desire to repent and trust in Christ, he or she should not delay and should not harden his or her heart (cf. Heb. 3:7–8; 12:17). This ability to repent and desire to trust in God is not naturally ours but is given by the prompting of the Holy Spirit, and it will not last forever. “Today, when you hear his voice, do not harden your hearts” (Heb. 3:15).'
Grudem, Systematic Theology p.498