Christianity is singular. Meaning by necessity it has to stand apart from everything on earth. Just as everything on earth has a beginning (a threshold) to its place. As you approach, it is not then all of a sudden it is. So what is the threshold of Christ in us?
Spurgeon points at it with this:
“Genuine, spiritual mourning for sin is the work of the Spirit of God. Repentance is too choice a flower to grow in nature’s garden. Pearls grow naturally in oysters, but penitence never shows itself in sinners except divine grace works it in them. If thou hast one particle of real hatred for sin, God must have given it thee, for human nature’s thorns never produced a single fig. ‘That which is born of the flesh is flesh.’”