What does Article 31 of the Constitution refer to?

Article 31 of the Mexican Constitution lists the obligations of Mexicans. These include making sure one’s children attend school, receiving civic and military instruction, and contributing to public spending, that is, paying taxes, in a proportional and equitable manner.

Don’t confuse it with Article 35, which lists the rights of citizens (such as voting and being voted for), or Article 36, which lists the obligations that apply specifically to citizens.