John 16:2

They shall put you out of the synagogues: yea, the hour cometh, that whosoever killeth you shall think that he offereth service unto God.

The apostles might have anticipated their expulsion from synagogues, for they had witnessed what was done to the blind man (John 9:34); but, at this stage of their development, they could not have been aware of the frenzied hatred that would fall upon them when they began their worldwide proclamation of the gospel.

Out of the synagogues ... This was a penalty dreaded by every Hebrew, meaning loss of social acceptability, employment, and all access to the religious life of the community. Excommunicated persons were held to be worse than pagans and were the object of total rejection and hatred.

Killeth you ... The world's hatred of the apostles would never be abated by the mere penalty of excommunication; they would be murdered. Christ also revealed here that their murder would be motivated by religious considerations. As Barnes put it:

The people of God have suffered most from people who were conscientious persecutors; and some of the most malignant foes Christians ever had have been in the church, professed ministers of the gospel, persecuting them under pretense of zeal for the cause of purity in religion.[3]

Dummelow tells us that "There is a Jewish saying, `Every one that sheddeth the blood of the wicked, is as he that offereth a sacrifice.'"[4] Paul himself, before his conversion, was a conspicuous example of this very type of persecutor.

[3] Alfred Barnes, Notes on the New Testament (Grand Rapids, Michigan: Baker Book House, 1954), p. 344.

[4] J. R. Dummelow, Commentary on the Holy Bible (New York: The Macmillan Company, 1937), p. 801.