To the mass of ill-deserving sinners on earth, God holds out the gospel that any person who looks in faith to the Son will receive eternal life. But what if no one actually responded to that message? What if not one person took advantage of this opportunity? Because this is the actual condition we find man in - No amount of outward appeals by God to man's heart or reason will suffice to persuade him to come to Jesus. Left to himself he is hopelessly given over to darkness. If he refuses to come it isn't because God is holding him back or coercing him against his will in the way of sin. This is what man wants in his heart of hearts.
Does the love of God allow Him to simply leave all people in the misery of their own stubborn willful choice because to do otherwise would violate their so-called free will? It would certainly be just but God loves His people too much to leave us to our own stubborn will. So out of the mass of ill-deserving sinners he still has a plan to save them in spite of their obstinacy. If people are to come to faith in Jesus they also need mercy to be delivered from themselves - from their own hardened heart. Because it is in man's heart that sin resides and holds him in inescapable bondage. We need God to give us, not just a way to choose, but a supernatural disarming of our innate hostility to God and an implanting of a new heart which loves God - which sees the beauty truth and excellency of Jesus Christ. (John 6:65, 65, 37; Ezek 36:26' Rom 9:15, 16)