David's response after his infant son's death is one of the most theologically condensed statements about afterlife hope in the Old Testament: "I shall go to him, but he shall not return to me" (2 Samuel 12:23). After the child died, David ended his fast and resumed eating. His servants were confused. His explanation contains a quiet, specific confidence: the child cannot come back, but David will go to where the child is. He did not say "he is in a better place" in the general way people use that phrase. He said "I shall go to him" — which implies somewhere specific that both would inhabit.
Matthew 19:14 — "Suffer little children, and forbid them not, to come unto me: for of such is the kingdom of heaven" — was Jesus' rebuke of his disciples who were turning children away. Jesus received children. He received them specifically, in his arms. The God who said this does not turn children away in death.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.