How do we know that Jesus' teachings are authoritative?

The authority of Jesus' teachings is affirmed throughout the Gospels. In Luke 9:44, He instructs His disciples to 'let these sayings sink down into your ears,' indicating the weight of His words. His impending betrayal, death, and resurrection fulfill Old Testament prophecies, showcasing His divine mission and authority as the Son of Man. This certainty in His authority is complemented by the apostles’ later teaching, recorded in Acts, as they are inspired by the Holy Spirit to convey the truths necessary for the church.