This is the height of true wisdom: to be simple but with understanding; for the soul of a little child is pure from all worldly passions. Towards them who have vexed him he bears no resentment, but goes to them as to friends as if nothing had happened; and however he is chastised by his mother; he seeks after her, and he prefers her to all others. He prefers being with his mother wearing rags than with a queen in splendor. For a child does not judge by poverty and wealth, but by love.
In a similar way, he who lives according to the good ways of his mother the Church, honors nothing above her, not even pleasure, which is the queen of many. That is why Jesus said "of such is the kingdom of God," that is, of persons who have both in their intention and their work the harmlessness and simplicity which children have. Therefore the Lord also adds, "Truly I say to you, Whoever shall not receive the kingdom of God as a little child, he shall not enter therein."
We are also to receive the kingdom of God, that is, the doctrine of the Gospel, like a little child. Because as a child, when he is taught, does not contradict his teachers, nor put together reasonings and words against them, but receives with faith what they teach, and obeys them with awe, so are we also to receive the word of the Lord with simple obedience, and without any argument. It goes on: "And he took them up in his arms, put his hands upon them, and blessed them", implying that the lowly in spirit are worthy of His blessing, grace, and love.