“When the Counselor comes, whom I will send to you from the Father, the Spirit of truth who goes out from the Father, he will testify about me. And you also must testify, for you have been with me from the beginning.
“All this I have told you so that you will not go astray. They will put you out of the synagogue; in fact, a time is coming when anyone who kills you will think he is offering a service to God. They will do such things because they have not known the Father or me. I have told you this, so that when the time comes you will remember that I warned you. I did not tell you this at first because I was with you.
“Now I am going to him who sent me, yet none of you asks me, ‘Where are you going?’ Because I have said these things, you are filled with grief. But I tell you the truth: It is for your good that I am going away. Unless I go away, the Counselor will not come to you; but if I go, I will send him to you.” (John 15:26-16:7)
Wherever God is, there is his kingdom. The promised Counselor was the Holy Spirit, whose purpose was to testify about Jesus. Jesus also warned his disciples to expect persecution, ranging from expulsion from the synagogues, to actual physical harm. The Jewish people revolted against Rome barely forty years later. The Christians—still mostly all Jews—refused to participate, so the Sanhedrin officially expelled them all.
Jesus let them know ahead of time so that they could understand that what they faced was not something God didn’t anticipate. Like a dog at the vet, who can see nothing and understand nothing beyond the discomfort and pain, the poking and prodding without ever understanding the reason for the situation, so Jesus was attempting to let his disciples see the bigger picture. He wanted them to understand that as painful as it might be, God was always with them.
We don’t have to face the problems of life by ourselves. Jesus is always with us, because his Spirit lives inside of us. We’re never separated from God’s kingdom.