Jesus's ministry was exclusively to Jews (Matt 15:24; Matt 10:5)—the Sermon on the Mount is a Jewish address, not a Gentile one

Matthew 15:24 explicitly states Jesus was sent only to the lost sheep of the house of Israel. Matthew 10:5 sends disciples only to Jews, not Samaritans or Gentiles. Jesus's teachings in Matthew 5 were addressed to a purely Jewish audience in a pre-Gentile-mission context. Even Matthew 6:32 ("the Gentiles seek after these things") assumes a Jewish audience being told not to be like Gentiles. How these teachings apply to Gentiles must be determined from Acts and the Epistles.