Roman soldiers wore sponges imbibed with vinegar on a string around their neck, for drinking. The vinegar was added to keep the moist sponge from rotting. So m

Roman soldiers wore sponges imbibed with vinegar on a string around their neck, for drinking. The vinegar was added to keep the moist sponge from rotting. So most probably the correct interpretation is that the Roman soldier passed his own personal drinking bottle to Jesus.