It was through this hallowed Side that the last drops of blood were shed, as final testimony of love elicited by the God-Man, toward those whose cause He was so eloquently pleading before the throne of His Heavenly Father. Hence, nothing is more natural than that it should attract very special attention. The deep devotion St. Augustine (d. 430) entertained toward the Sacred Side can be gauged by the following words. "The Evangelist fittingly states that the soldier opened His Side, in order that in It, so to speak, may be opened the gate of life, through which issued the Sacraments of the Church, without which no one can enter the path leading to eternal life. Thus, the second Adam with bent head slept on the cross that Spouse may be created for Him issuing from His Side. What is there purer than this blood What more healing than this wound ?"
It is not to be presumed that the devotion to the Sacred Side was exclusive of the Sacred Heart. Father Galliffet adduces some reasons of his own to prove that the lance of the centurion after it pierced the Side of Christ penetrated into His Sacred Heart. He also quotes from the writings of St. Gregory Nazianzen, St. Bernard, St. Thomas Aquinas, St. Francis de Sales, and others, who share his belief. Hence, we may reasonably suppose that the two wounds, viz., that of the Side and the Heart of Christ, were never disassociated, but honored always unitedly.
D. From the foregoing we can see how gradually and instinctively the popular mind was drawn nearer and nearer to the Sacred Heart, which was destined to be the object of favored cult. While the Sacred Heart, for long time, was not proposed for worship as separate object, nevertheless, the writings of the early Fathers contain many explicit allusions to It. St. Augustine, St. Ambrose, and St. John Chrysostom speak repeatedly of the Sacred Side and the blood issuing from it, but as far as we can ascertain they make no explicit mention of the Heart of Christ. St. Paulinus of Nola (d. 431) is the first to mention it explicitly. He pictures St. John as resting his head on Jesus' breast, and drawing deep mysteries "from His Heart, as from the fountain of the creative Wisdom, being thereby inebriated by the Holy Ghost." Perhaps the most striking words of any used by an early writer come down to us from St. Anselm (d. 1109), Arch bishop of Canterbury. "What sweetness," he says, "in this pierced Side. That wound has revealed us the treasures of His goodness, that is to say, the love of His Heart for us."