a) What is the Fourth Commandment of God?
The Fourth Commandment of God is: Honor your father and your mother.
This commandment instructs us to respect, love, obey, and help our parents, brothers and sisters, priests, teachers, officers, and, in general, those who have authority over us or are older than us.
b) Why should an Altar Server know and live the Fourth Commandment?
God gives these persons special graces to guide us. Besides, they probably have already gone through situations like what we currently experience or have been trained in things that could help us.
Altar Servers should be examples of docility towards their superiors, not only in the Church premises, but also in the family, in school, and elsewhere.