In the context of the 16th century why would the spanish crown have believed the requerimiento gave justification to its actions?

The Spanish Requirement of 1513 (Requerimiento) was a declaration by the Spanish monarchy, written by the Council of Castile jurist Juan López de Palacios Rubios, of Castile's divinely ordained right to take possession of the territories of the New World and to subjugate, exploit and, when necessary, to fight the native inhabitants.

The Requerimiento (Spanish for "requirement" as in "demand") was read in Castilian[citation needed] to Native Americans to inform them of Spain’s rights to conquest. Those who subsequently resisted conquest were considered to harbor evil intentions.[citation needed] The Spaniards thus considered those who resisted as defying God’s plan, and so used Catholic theology to justify their conquest

a.

congress passed laws allowing for free passage between states.