Acts warnings

In Acts 21 Paul is warned several times that going to Jerusalem will be terrible for him. But Paul believes that he is supposed to go, no matter what. Was the Spirit warning him not to go through the voices of the people, or were the people warning him not to go in light of what the Spirit had revealed? I think our preacher missed a bit: John 16:4: "I have spoken to you, so that when their hour comes, you may remember that I told you of them."

I gather from Ephesians that Paul could do with a little encouragement himself now and then, and knowing, when the disasters hit, that it was part of the plan and not a screw-up on his part, was probably encouraging.