Why was the decree issued to kill all the boy babies under two years old?
The decree was issued to destroy the Christ child. Satan, symbolized as the dragon, stood ready to devour the woman's child as soon as He was born. Extending the slaughter to all boys under two guaranteed that the child born at Bethlehem would be included.
Les explains that the dragon in Scripture symbolizes Satan, who had rebelled against God and took a third of the angelic host with him. The woman represents Israel, and her delivery refers to the birth of the Christ child at Bethlehem. Satan stood before the woman to devour her child as soon as it was born—he intended to kill the Christ child. Therefore the decree went out to kill all boy babies under the age of two, ensuring that it would include this child born at Bethlehem. The man-child was later caught up to God and His throne, a reference to the Ascension, and He is the one destined to rule all nations with a rod of iron as King of kings and Lord of lords.