This lesson discusses why God cannot refuse those who repent and seek forgiveness. People can refuse to repent, but God will never deny repentance and forgiveness to anyone.
"If the wicked turns from all his sins which he has committed and observes all my statutes and practices justice and righteousness, he shall surely live, he shall not die. All his transgressions which he has committed shall not be held against him. Because of the righteousness which he has practiced he shall live. The Lord God declares, Do I have any pleasure in the death of the wicked, rather than that he should turn from his ways and live? ...Again, when a wicked man turns away from his wickedness which he has committed, and practices justice and righteousness, he will save his life. Because he considered and turned away from all his transgressions which he had committed, he shall surely live, he shall not die." (Ezekiel 18:21-22).
"Create in me a clean heart O God, and renew a steadfast spirit within me. Do not cast me away from your presence, and do not take your Holy Spirit from me. Restore to me the joy of your salvation, and sustain me with a willing spirit... A broken and contrite heart, O God, you will not despise" (Psalms 51:10-17).
"Come now and let us reason together says the Lord. Though your sins are as scarlet they shall be as white as snow, though they are red like crimson, they shall be as wool. If you consent and obey, you will eat the best of the land, but if you refuse and rebel, you will be devoured by the sword. Truly the mouth of the Lord has spoken" (Isaiah 1:18-20).
"God is not willing that any should perish, but that all should come to repentance" (2Peter 3:9).
"If we confess our sins, God is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness" (1John 1:9).
"Let the one who is thirsty come, let the one who wishes take the water of life freely" (Revelation 22:17).
Now that those passages are before you, let me make three simple points in relation to the so-called "unforgivable sin"...
The above promises cannot be contradicted by anything said elsewhere in the Bible. It is the simplest and most fundamental principle of interpreting the Bible that what the Bible says in one place must be interpreted to harmonize with what the Bible says everywhere else. As Jesus said, "The scripture cannot be broken" (John 10:35).
If there were any passage in the Bible which teaches that a person can repent and come contritely to God seeking forgiveness yet be turned away by God and refused, then not only does the Bible contradict itself, but the grace of God is limited.
The gifts of God are perfect and his grace is not fickle. "Every good thing bestowed and every perfect gift is from above, coming down from the Father of lights, with whom there is no variation or shifting shadow" (James 1:17).
If God reserved even one sin as unforgivable, he would shut out from his grace and mercy all who had committed that sin, and the atonement of the blood of his Son would no longer be for the whole world (1John 2:2).
God in Christ is the "author of eternal salvation" and "the author and perfector of our faith" (Hebrews 5:9, 12:1-2).
If God refused to forgive even one sin, then for those who had committed that sin he would be the author of eternal damnation. But God refuses grace to none and offers it to all. Many, however, refuse him.
People are the authors of their own damnation when they refuse to repudiate Satan, repent of their sins, and obey God.
One of the definitions of those whose sin is never forgiven is that "it is impossible to renew them to repentance" (Hebrews 6:6).
If a person is renewed to repentance after falling away, then God welcomes that person and forgives. After considering the scriptures and three points above, I think you will see that anyone —whosoever desires— may "draw near with confidence to the throne of grace... and find grace to help in time of need" (Hebrews 4:16).