When the Saints Apostles put the problem of greatness in God’s Kingdom [Mat. 18, 1], the Lord spoke to them about return, ie about repentance, through which we arrive to be like the infants [Mat. 18, 2, BYZ]. For He does not ask from us the nescience of infants, but their lack of conscious malice, their lack of duplicity. And the simpleness of holiness is interior innocence, is cleansing of the heart, and just therefore it goes into the Kingdom of God.
Children play with the danger because they do not know it can kill them. Children believe in everything that we tell them. Therefore, many believe that the infants are „saints” in comparison with them. But the Church, on the contrary, believes that all the infants must be exorcised before Baptism, because all are dwellings of the demons.
And, in Baptism, every infant becomes a dwelling of God, for that the glory of the trinitarian God descends into the baptized. Fact for which, from Baptism, the infant is the saint of God, if he remains in His glory.
Why the infants are the paradigms of ghostual life? For that the simpleness and the interior cleanness are ultimate virtues of holiness.
The humbleness makes us simple. The divine love is full of simpleness and cleanness. The faith is sight of the divine, which are simple, for that and the hope expects simple things. And, in general, the life leads us to an ever greater simplification of us, for that our maturation means the contentment with all fewer things from here, from the earth.
Therefore, we are born nescient, we learn more and more things, the teaching does not complicate us, but it simplifies us, and, at elderness, we arrive again to the simpleness of infants in the face of danger. But, if we ghostually advanced, then we reach at the ghostual simpleness that God demands of us. Because the holiness is a continuous awareness of our life with God.
And who sanctifies himself, that one has to enter into the Kingdom of the heavens [Mat. 18, 3]. For that this entry in Kingdom is voluntary and conscious. And the Saints are the saved.