What does Mark 15:36 mean?
It's reasonable to think that someone who'd had nothing to eat or drink since the night before would be thirsty the next afternoon. Still, this is the only time Jesus specifically expresses discomfort on the cross (John 19:28). Doctors suggest that His thirst is one of the many indications He is suffering from hypovolemic shock, or blood loss.It is not unusual for Roman soldiers to scourge their victims, but it appears they whipped Jesus with special vigor. Pilate may have hoped that by beating Jesus the Sanhedrin would be satisfied and Jesus wouldn't have to be crucified. He was wrong (Luke 23:16–25). The guards used a whip of leather thongs braided with balls of lead and sharp pieces of bone to flay Jesus' flesh. The Mosaic law limited corporal punishment to no more than forty lashes (Deuteronomy 25:3); the Romans are free to whip their victims until bones and bowels are revealed. Jesus' inability to carry His heavy crossbeam supports the theory of blood loss (Mark 15:21), as well as His relatively short stay on the cross. Most crucifixion victims live for two or three days; Jesus lasts six hours (Mark 15:25, 34).
One of the signs of hypovolemic shock is extreme thirst. The body has lost more than twenty percent of its blood, and the kidneys stop functioning to preserve what body fluid is left. The heart beats faster, trying to move the decreased volume of blood. Fluid collects in the cavity around the heart and lungs. This fluid escapes when the guard pierces Jesus' chest with a spear (John 19:34).
Most crucifixion victims die of asphyxiation. They can only breathe by holding their weight on the nails through their feet. Their body grows more and more fatigued until they cannot push themselves up anymore. At that point, they have no breath. When Jesus dies, He shouts (Mark 15:37), impossible for someone who cannot breathe, but very possible for someone who dies of the medical equivalent of a broken heart.
The "sour wine" offered here is probably a common, cheap beverage, made mostly of water and eggs, with a splash of wine vinegar to keep it from spoiling. Why the executioners would allow this, given that it would make Jesus survive longer, is unknown. It's possible the soldiers are already beginning to question their role in this event (Mark 15:39).