15 Then they also brought infants to Him that He might touch them; but when the disciples saw it, they rebuked them. 16 But Jesus called them to Him and said, “Let the little children come to Me, and do not forbid them; for of such is the kingdom of God. 17 Assuredly, I say to you, whoever does not receive the kingdom of God as a little child will by no means enter it.”
Luke 18:15-17
Jesus blesses little children. Here people are bringing their children and infants to be blessed by Jesus. The disciples rebuke the people, however Jesus stops them and does not waste the opportunity to teach all present. Children are innocent, pure, bursting with faith and wonder. Christ makes it clear that this is how they should receive the kingdom of God, as a child receives a perfect gift.
Without approaching the kingdom as a child would, they will not enter it.