God looks for child-like faith in his followers, for them to put all their trust and confidence in Him. Child-like is not childish. Jesus is speaking of mature, deep, lasting faith and an acknowledgement that He is the way to God. The uncomplicated, joyous, unconditional welcome given by a child to a loved one is how we should relate to Jesus and welcome the presence of God into our lives. That is the path to spiritual greatness.
Lord, I welcome you with tears of joy. Teach me your love and give me the grace to praise you with simplicity, joy in my heart and warmth of embrace as I bring you once more into my life today.