This bill, titled the "Finish the Wall Act," mandates the immediate resumption of border wall system construction along the international border between the United States and Mexico. Within 24 hours of enactment, the Secretary of Homeland Security must restart all construction activities that were underway or planned prior to January 20, 2021, and is prohibited from canceling any related contracts entered into before that date. The bill explicitly requires the expenditure of all funds appropriated or obligated for border wall construction since October 1, 2016. The Secretary of Homeland Security must submit an implementation plan within 30 days to complete the border wall system construction by September 30, 2026. A more comprehensive plan, due within 90 days, will detail the completion of tactical infrastructure and technology elements , including quarterly benchmarks and cost estimates, utilizing both existing and future appropriations. The bill also ensures that all written agreements between the Department of Homeland Security and various stakeholders regarding border wall construction are honored. Furthermore, the legislation requires the Secretary of Homeland Security to certify within 14 days of enactment that U.S. Customs and Border Protection is fully compliant with the DNA Fingerprint Act of 2005 at all border facilities processing adults in custody.