John Calvin provides some helpful comments on passages like Hebrews 6:4-6, 10:26, and 12:7.
These passages in Hebrews say,
4 For it is impossible, in the case of those who have once been enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit, 5 and have tasted the goodness of the word of God and the powers of the age to come, 6 and then have fallen away, to restore them again to repentance, since they are crucifying once again the Son of God to their own harm and holding him up to contempt. – Heb 6:4-6
For if we go on sinning deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins. – Heb 10:26
For you know that afterward, when he desired to inherit the blessing, he was rejected, for he found no chance to repent, though he sought it with tears. – Heb 12:17
Calvin, is this saying that God will refuse forgiveness to someone who repents?


Grant Osborne has popularized an idea known as the ‘hermeneutical spiral’ according to which various elements like exegesis of the text, biblical theology, systematic theology, historic theology, etc. create a ‘hermeneutical spiral’ something like the following admittedly simplistic explanation: