Holy perfection demands holy perfection. When we all fell in Adam, God did not lower His holy standard to accommodate man's sin. No ... God will not compromise His holy character because, to do so, He would no longer be holy and thus no longer be God. So His demand for holy perfection remains even though fallen men are morally impotent to perfectly live up to His holy standard. Left to our flesh we have no power to raise ourselves out of our misery. And the soul that sins must die (Ezek.18:20). What can be done? It sounds hopeless.
In mercy, God came in the flesh in Jesus Christ as the only person to ever live without sin and who died a death He did not deserve, taking the place of all the rebellious sinners who believe in Him. But men STILL love darkness (John 3:19-20) and will not believe (Rom 3; 1 Cor 2:14) That is why, in addition to outwardly calling people to believe the gospel - a gospel which is a stumbling block to Jews and foolishness to Gentiles, the Spirit must also inwardly call and quicken (1 Cor 1:23-24; John 6:63) - why salvation must be all of grace (Eph 2:8-9) and why works are woefully insufficient. That is why, in love He set apart a people for himself to save out of the world; people from every tribe, nation, language and people (Rev 5:9). For if He left us all to ourselves to our own desires and fallen wills to make the choice - the choice our own fallen flesh - no one on earth would have hope for eternal life. No he must remake us, renew us in the Spirit if we are to see the truth, beauty and excellency of Christ and so believe in Him.