“Are cherubs the spirits of dead babies?”
In the gospel of Matthew, the Lord Jesus says this about children: “See that you do not despise one of these little ones. For I tell you that in heaven their angels always see the face of my Father who is in heaven.”
Some readers take this to mean that children who die before the age of accountability go straight into the presence of God and become angels. This line of thought probably led to the popular depiction of angels as chubby, naked infants with wings. Google “cherub” and you inevitably get something like what appears above.