I've had people tell me these very words. When I think about who has proved it, only two people come to mind who seem to have made a real effort to prove it (only initials here of who they are: Thank you JT & MF for even trying), & only 1 has completely fulfilled those words. That one is Jesus Christ :)
The Wonder Weeks explains why and when your baby is most likely to sleep less calm. What happens inside your baby's head what makes him/her sleep and eat differently and what you can do to help your baby through this (and other!) phase(s).