Original sin.
That’s being born without holiness, the Tree of the Knowledge of Good and Evil was not just about evil, but about knowing good and evil … of being in the case of a creature reduced to merely moral beings rather than remain by dint of creation holy beings (yes, derivative holiness, but still holiness of that sort).
The cross, the resurrection and the gift of the Holy Spirit deals with the need to be holy to stand before the Lord (there is apparently an issue of culpability, but that is not the one and only Gospel given).