Why Jesus chastised Saul

Saul, Saul, why dost thou persecute Me?
ACTS 9:4

How could Saul be persecuting Our Lord Who was glorified in Heaven? Why should the Voice from Heaven say: “Saul, Saul, why dost thou persecute Me?”

If someone stepped on the foot, would not the head complain because it is part of the body? Our Lord was now saying that in striking His Body, Paul was striking Him. When the Body of Christ was persecuted, it was Christ the Invisible Head Who arose to speak and to protest. The Mystical Body of Christ, therefore, no more stands between Christ and an individual than His physical Body stood between Magdalen and His forgiveness, or His hand stood between the little children and His blessing. It was through His human Body that He came to men in His individual life; it is through His Mystical Body or His Church that He comes to men in His mystical corporate life.

Christ is living now! He is teaching now, governing now, sanctifying now—as He did in Judea and Galilee. His Mystical Body or the Church existed throughout the Roman Empire before a single one of the Gospels had been written. It was the New Testament that came out of the Church, not the Church which came out of the New Testament. This Body had the four distinctive marks of life; it had unity, because vivified by one Soul, one Spirit, the gift of Pentecost. As unity in doctrine and authority is the centripetal force which keeps the life of the Church one, catholicity is the centrifugal force which enables her to expand and absorb redeemed humanity without distinction of race or color. The third note of the Church is holiness, which means that it endures on condition that it keep itself healthy, pure, and free from the disease of heresy and schism. This holiness is not in each member but rather in the whole Church. And because the Holy Spirit is the soul of the Church, it can be the Divine instrument for the sanctification of souls. The sunlight is not polluted because its rays pass through a dirty window; neither do the sacraments lose their power to sanctify because the human instruments of those sacraments may be stained. Finally, there is the work of apostolicity. In biology, Omne vivum ex vivo or “All life comes from life.” So too the Mystical Body of Christ is apostolic, because historically it took its roots in Christ and not from a man separated by centuries from Him. That is why the infant Church met to choose a successor of Judas who had to be a witness of the Resurrection and a companion of the Apostle. – from Life of Christ (1958)