John 16
Warning of persecution
“I have said these things to you so that you wouldn’t be caused to stumble. They will put you out of the synagogues. Yes, the time is coming that whoever kills you will think that he offers service to God. They will do these things because they have not known the Father nor me. But I have told you these things so that when the time comes, you may remember that I told you about them. I didn’t tell you these things from the beginning, because I was with you.
Jesus tells the disciples why he is warning them: so they will not fall away. They will be expelled from synagogues, and some will kill them thinking they are serving God. He says he did not speak of this earlier because he was with them.
What does this mean?
"Be offended" (KJV) means to be made to stumble or lose faith. "Doeth God service" (KJV) means offers worship or service to God.
Historical context
Expulsion from the synagogue appears also at 9:22 and 12:42. Paul's letters describe how he once persecuted followers of Jesus out of zeal for God (Galatians 1:13-14), an example of the kind of opposition described here. Many scholars think these verses reflect conflicts experienced by the community behind John's Gospel.
Why does it matter?
Jesus' foreknowledge is meant to steady the disciples: when trouble comes, they will remember that he warned them. These verses complete the thought begun in 15:18.
Editorial notes, not scripture.