1 sn If it was obvious to the soldiers that the victim was already dead it is difficult to see why one of them would try to inflict a wound. The Greek verb pierced (νύσσω, nussw) can indicate anything from a slight prod to a mortal wound. Probably one of the soldiers gave an exploratory stab to see if the body would jerk. If not, he was really dead. This thrust was hard enough to penetrate the side, since the author states that blood and water flowed out immediately.
2 sn How is the reference to the blood and water that flowed out from Jesus’ side to be understood? This is probably to be connected with the statements in 1 John 5:6-8. In both passages water, blood, and testimony are mentioned. The Spirit is also mentioned in 1 John 5:7 as the source of the testimony, while here the testimony comes from one of the disciples (19:35). The connection between the Spirit and the living water with Jesus’ statement of thirst just before he died in the preceding context has already been noted (see 19:28). For the author, the water which flowed out of Jesus’ side was a symbolic reference to the Holy Spirit who could now be given because Jesus was now glorified (cf. 7:39); Jesus had now departed and returned to that glory which he had with the Father before the creation of the world (cf. 17:5). The mention of blood recalls the motif of the Passover lamb as a sacrificial victim. Later references to sacrificial procedures in the Mishnah appear to support this: m. Pesahim 5:3 and 5:5 state that the blood of the sacrificial animal should not be allowed to congeal but should flow forth freely at the instant of death so that it could be used for sprinkling; m. Tamid 4:2 actually specifies that the priest is to pierce the heart of the sacrificial victim and cause the blood to come forth.