I do not believe God leaves any person without the ability to hear, understand, and accept the Gospel. Even the most radical Buddhist, atheist, ect, will somehow, some way have the right circumstances come about in their life where they can either make the right decision or the wrong decision. Some people might only have one real opportunity to repent and believe, after that God might allow them to continue in their hardened state.
If God demanded that in order to be saved a man had to walk on the ceiling, it would be reasonable to accuse God of keeping people from salvation. But man's inability is not of that nature. The Scriptures are widely available, and in countries where it isn't, the Bible is broadcast in by organizations like SAT-7. Man's inability is not physical, but moral.
'And this is the condemnation, that the Light has come into the world, and men loved darkness rather than light because their deeds were evil' (John 3:19).
'Because, although they knew God, they did not glorify Him as God, nor were they thankful, but became futile in their thoughts, and their foolish hearts were darkened' (Romans 1:21).
Perhaps I may give a word of testimony. My parents were only vaguely religious and not church-goers, but they were diligent to have me Christened into the Church of England as a tiny baby. When I was 12, I received a
Gideon New Testament at school (this is Britain; no separation of Church and State here) and promptly stuffed it away in a drawer and forgot about it. Shortly afterwards, my mother became very ill and was whisked off to hospital in an ambulance at 2 am one night. I remembered my NT, fished it out of the drawer and read the 'helps' at the front. I did receive comfort and was able to say a prayer for my Mum and eventually to get to sleep. I read the whole NT through at this time.
At 13, I was 'confirmed,' but I had no real knowledge of God or the Lord Jesus. I think I could have been a Jew or a Moslem more easily than a Christian - I didn't understand what Christ had done. I read the entire Bible through around that time, but I still didn't understand it. Shortly after that, adolescence kicked in, and I forgot all about God and spent all my time drinking and chasing girls - not with any great success as to the latter, but not for want of trying! At University, I read the NT through again, but still didn't make anything of it. I understood the words, but not the message. I was approached by the University Christian Union a few times, but in my arrogance, I thought of myself as somehow being right with God - madness! - and never bothered with them.
It was not until I was 38 that
'it pleased God, who ...... called me by His grace, to reveal His Son in me.' Mrs Marprelate and I were invited to an evangelistic Bible Study, and for the first time, the penny dropped! Ever since then (1991), I have read and studied avidly and The Lord has been pleased to open my eyes to understand, to some degree at least.
So if learning and reading the Bible could make a Christian, I would have been one years before, but it is God who must open the heart to understand. But the Lord Jesus turns no one away who is sincere (John 6:37). He says,
'.....Ask, and it will be given to you; seek and you will find; knock and it will be opened to you. For everyone who asks receives, and to him who asks it will be opened. .......If you then, being evil, know how to give good gifts to your children, how much more will your heavenly Father give the Holy Spirit to those who ask Him! (Luke 11:9-13). The only caveat here is that the commands 'ask,' 'seek,' 'knock' are in the Present Continuous tense - 'Keep asking, don't stop seeking, knock continually!'
'You will find Him if you seek Him with all your heart and with all your soul' (Deut. 4:29; cf. Psalm 40:1-3).
