"Law is the command of the sovereign" is said by the famous jurist John Austin in his Command Theory. Austin in his Command Theory described "law is the command of sovereign backed by sanctions" which means the law is made by the sovereign body of the state and if anybody does not obey law then the state will punish him/her for ignoring the command of the sovereign.
Austin was from the United Kingdom who developed Analytical School and was also the father of Analytical School. Austin opposed the traditional approach of law-making of theories that law is guided by morality, religion, and god and separated morality from law. According to Austin, "law is the command of sovereign backed by sanctions."
Austin focused on law from a positive aspect as what it is not what it should be as in normative. According to him, law means what it is now and not what it was in the past and what it will be in future. Austin said that law is not associated with morality and is independent of morality.
Austin in his Command Theory said law is the command of sovereign backed by sanctions in which there are four elements he described i.e. sovereign, command, duty, and sanctions.
1. Sovereign: Sovereign means superior political authority and superior political authority may be a King in a Monarchical system whereas Parliament may be the superior political authority in a Parliamentary system of government. According to Austin, "law is the command of sovereign and if there is no sovereign then there is no law because the law-making authority is vested in sovereign."
2. Command: The order issued by sovereign political authority is the command and it is binding on everyone.
3. Duty: It is the duty of everyone to follow and obey the laws made by state.
4. Sanctions: Sanction means punishments given to those who disobeyed laws and not followed the law.
Now it is clear that law is the command of the sovereign but with the following example, it will be more clear how law is the command of the sovereign backed by sanctions.
For example, Muluki Ain is a law made by the sovereign political authority i.e. Parliament of Nepal. Section 177 of Muluki Criminal (Code) Act, 2074 clearly states that No person should intentionally kill, or do, or cause to be done, any act causing the death of, another person otherwise a person who commits or causes to be committed, the such an offense is liable to the sentence of imprisonment for life.
Here Parliament of Nepal is the sovereign body, not committing any murder is the command of the sovereign, it is the duty of everyone to no to commit any murder, but if someone disobeyed the law and kills anyone then the state will arrest such person, prosecute and punish him.
Similarly, Environment Protection Act prohibits a person to do any activities which endanger environmental conditions and cause any kind of pollution but if anyone does any activities that cause and affects the environment badly then such person will be punished by the state as prescribed by law.
Now, it is clear that law is the command backed by sanctions where sovereign means supreme political authority, and everyone must follow that law made by it. If anyone did not follow then such a person will be punished. Law is binding and imperative in nature and it has sanctions capacity to enforce the law.