Can the non-elect really be regenerated – be given a new heart and receive the Holy Spirit and yet fall away from God’s mercy? Why, yes. And this explains the infamous stumbling block to the calvinists – Hebrews 6 and 10. Those passages about falling away and rendering it impossible to be renewed again to repentance, having no more sacrifice for sins but only fiery judgement – they’re not talking about the elect. It’s about the non-elect who are conditionally regenerated but fall away always by their own self-determinism.
This way, every mouth is stopped before God and He is justified and overcomes when He is judged of His ways by mere mortals. This is not something God is obligated to do – but which He chooses to do to make apparent where the fault lies. Now none are with excuse – for God has done to the utmost, given His precious Son and shown mercy and given His Holy Spirit – with simply the conditional to choose life. And non-elect man throws it all away – and for this he is condemned (John 3:19).
King Saul
Consider king Saul. Was he not given a new heart and given the Holy Spirit (1Sam 10: 6-7, 9-10) ? One may argue that this was the Old Testament where the giving of the Holy Spirit was only for specific temporal purposes and did not in any way denote salvation. I might have a different interpretation there, but nonetheless, it still foreshadows how God works. If Israel’s exodus, led by a prophet, from the land of slavery to the Promised land is limited to only temporal events, wouldn’t we be missing out on what is foreshadowed of Jesus’ works now?
God counsels against a king for His people. The people reject His counsel and demand their own way (1Sam 8:7). God warns them of what their way would result in (1Sam 8:10-18). They ignore to heed this (1Sam 8:19). God then anoints the man perceived as the best from among all flesh (1Sam 10:23-24) after equipping him with a new heart and God’s own Spirit to enable him to walk in obedience to God.
Even though God is displeased with Israel’s demand, He still gives them all that is needed, barring His own operational nature. The Master Scientist’s demonstration shows eventually what the flesh is capable of – in that king Saul falls away miserably. Had he continued to lean upon God thoroughly, his kingdom would’ve been established forever (1Sam 13:13) – but he proves that self-determinism always fails God’s conditional to trust Him and deny self/flesh.
King David
Having seen the effects of self-determinism, the demonstration continues with what would happen when God Himself works in a king – and we see David anointed a man after God’s own heart set on an eternal throne. David is the foreshadow of how the Spirit of Christ overcomes and perseveres compared to the failures of the flesh. The sure mercies of God are upon David and his son, Solomon – and this is contrasted against the conditional mercy upon king Saul (2Sam 7:15).
In exactly the same way, God’s sure mercies are upon all the elect. But this is not to say God is not merciful at all over the non-elect. There is conditional mercy shown and God genuinely desires that they be saved within His sovereign choice to factor in their self-determinism. When they fall away by their own selves, filling up their measure of iniquity, God then turns in wrath and condemns them to destruction.