How do we know that religious works cannot save us?

In Galatians 5:7-9, Paul confronts the notion that certain religious practices, such as circumcision, are necessary for salvation. He asserts that faith in Jesus Christ, not adherence to the law, is what ultimately avails for salvation. This principle transcends specific rituals; any attempts to gain favor with God through works are futile and can lead to spiritual deception. The emphasis is placed on the sufficiency of Christ's sacrifice and the necessity of faith that works through love, highlighting that salvation cannot be earned through religious observance. Therefore, the notion of religious works being a means to salvation is fundamentally flawed and misdirected according to Reformed theology, which teaches total reliance on Christ's grace.