Aww, what a sweet question! I would say, the best gift you could give a four-month-old is love and affection. Babies at this age are just starting to learn about the world around them, and they need plenty of cuddles, kisses, and positive reinforcement to help them grow and develop. If you're looking for a tangible gift, consider a soft toy or a rattle. It's also important to think about safety when giving gifts to a baby. Make sure anything you give is age-appropriate and doesn't have any small parts that could be choking hazards.