His reason for piercing the Heart of Jesus with his lance. Although objectively the blow of the lance seems cruel, Longinus’ motive was noble. The great concern Longinus shows towards the Blessed Mother. Mary obtains for him the grace of salvation.
Following is a condensed version of Maria Valtorta’s long chapter on the Crucifixion (609), in her work The Gospel as Revealed to Me, removing whatever is extraneous to the role of Longinus in this tragedy.
Four brawny men, certainly of the same category as the scourgers, jump from a path onto the place of the execution. They are wearing short sleeveless tunics, and in their hands they are holding nails, hammers and ropes, which they show to the condemned men scoffing at them. The crowd is excited with cruel frenzy.
The condemned men are ordered to undress. The executioners offer the condemned men three rags, so that they may tie them round their groins.
But Mary has noticed everything and She has removed the long thin white veil covering Her head under Her dark mantle, and on which She has already shed so many tears. She removes it without letting Her mantle drop and gives it to John so that he may hand it to Longinus for Her Son. The centurion takes the veil without any objection and, when he sees that Jesus is about to strip Himself completely, facing the side where there are no people, and thus turning towards the crowd His back furrowed with bruises and blisters, and covered with sores and dark crusts that are bleeding again, he gives Him His Mother's linen veil. Jesus recognizes it and wraps it round His pelvis several times, fastening it carefully so that it may not fall off.
Pope Innocent VIII holds the spear point.