The military is all about discipline. One of the first things a soldier or sailor or marine learns in boot camp is to obey orders, instantly and without question.
But with children, it’s a different situation altogether! Their young minds are not yet ready to process very much information at once. So when you tell them to wash their hands before dinner, all they may understand is that it’s time for dinner. So they show up at the table with unwashed hands.They are not being disobedient; they are only being kids!
To help them understand discipline, it’s important to use repetition and echo. Repeat your request, calmly, for them to wash their hands first, and then ask them to repeat what you just told them to do. Praise them for being able to repeat an order, even a simple one. Once you establish this as routine, your children will become comfortable with it and learn to respond somewhat like a soldier or sailor by doing it (sometimes after a bit of prodding!) and without asking too many questions (don’t expect miracles!)