‘O foolish men, and slow of heart to believe all that the prophets have spoken!’ was said by Jesus to

Jesus said "O foolish men, and slow of heart to believe all that the prophets have spoken!" to two travelers on the road to Emmaus. The travelers were discussing the events that had occurred in Jerusalem, including the crucifixion of Jesus. They were unaware that Jesus had been resurrected and was walking with them on the road. Jesus rebuked them for not understanding the prophecies in the Hebrew Scriptures that pointed to him as the Messiah. He explained to them the meaning of these prophecies and how they had been fulfilled through his life, death, and resurrection. Jesus' rebuke to the travelers reflects his frustration with his followers' lack of understanding and faith, despite his teachings and the testimony of the prophets.