When I was a kid, snakes fascinated me. I think it had something to do with the way they moved without legs, which just didn't jive with the way my elementary-school mind understood motion (It involved feet, wheels or a combination thereof made real in a red Schwinn Stingray).
One thing about them that jumped out as even more bizarre was how their bodies would continue to move after their death by beheading. Said method of death, carried out with a garden hoe, being the fate of any snakes found in my grandparents' garden, I now and again had the opportunity to test this theory. If you ran your finger along the body of the recently departed reptile, it would indeed react as though it were still alive, coiling and uncoiling in response.
But of course that was just a muscle response -- the snake's brain, such as it was, wasn't controlling its body from five or six feet away (Grandma could swing a mean hoe). The movements didn't have any purpose or function, and after a little while they quit, as the nerve and muscle tissue inside the snake deteriorated. Sometimes groups of people who have come to follow a teacher are like that as well. When the teacher leaves, for whatever reason, they may continue to do things the teacher did or follow the teachings they've learned. But without new leadership, the group isn't likely to be able to continue, especially if the teacher was a charismatic and effective leader.
Had Jesus been an ordinary teacher, then his movement would have faced the same possibility when he was killed. But because he was more than that, he returned to them and inspired them to do more than just an ordinary group of followers might do. They still had to deal with his absence, though, since he ascended to be with the Father some forty days or so after the Resurrection. Those followers could very well have veered off course or gotten themselves headed in the wrong direction, since the teacher they followed was the Son of God and had a supernatural vision no human teacher could hope to comprehend on his or her own.
That's where this "Advocate" Jesus talks about comes in. We know the Advocate as the Holy Spirit, and over the course of the first decades after Jesus, Christians came to understand that this Holy Spirit Jesus had taught them about was as much a part of God as the Father and the Son themselves.
And they began to understand they did not have to rely on their own memories of Jesus or those remembered things they might tell other people about him. Although not visible in human form the way Jesus had been, the Holy Spirit was able to guide and teach them as well. Believers who opened themselves to God's work could feel the Spirit leading them to take actions or make choices that were a part of that work.
Sometimes the things the Spirit might lead them to do seemed strange to people who didn't follow Christ. Jesus explained that here, when he says that the world -- at least the part of it that makes gods out of things or people other than God -- couldn't see him or understand him. So they wouldn't understand some of the things that people who followed him did or said. If they too began to open their hearts and minds towards what God wanted to do in them, they could begin to perceive and understand, and in fact they would find Jesus revealing himself to them.
For us today, we should understand that the Spirit works in us as it did in that first circle of believers, still moving and guiding us in doing God's will. And we should understand that sometimes those incomprehensible things we do draw people's attention and may actually prompt them to ask questions and begin their own journey of faith, based on wanting to know more about why we believers are the way we are. In the passage from today, Jesus says that knowing and keeping his commandments is a sign that we love him. In another place, he says that our love for one another will let people know we are his disciples. Showing love for one another in the body of Christ may be one of those incomprehensible things I mentioned above, and I know it's one I do too rarely.
Over the last couple of weeks, a lot of people have talked about the Second Coming, or Christ's return, mostly because a fairly obscure radio preacher bought a lot of ads predicting a date. When we say our creeds, we say we believe in Christ's return and the new creation, even if we don't get specific about when and how. But we believe it will happen, and we believe it will be unmistakable when it does.
Our job in the meantime is to point people at Christ, so that they might be ready whenever he returns. We allow the Holy Spirit to be at work in us so that we might know how to do that in a particular place and time, knowing what to say and what not to say, when to say it and when to keep silent. As our Advocate, the Holy Spirit mediates God's message to us so that we may do God's work. In a way, the Holy Spirit helps us show people a hint, however small and pale in comparison with the real thing it may be, of the Christ whose return we proclaim.
The sermon title has an apostrophe after "believer," to indicate that the advocate involved is one who works on behalf of those who believe in and follow Christ. But the purpose of all that work by the Holy Spirit is to take the apostrophe from the title and turn it into an exclamation point: Believers Advocate!