When Christians say they "know" Jesus, what do they mean? There could hardly be a more important question than that. When church people talk about their "personal relationship" with Jesus, what kind of relationship do they have? And how did this relationship come about? That last question is particularly important for the life of the church. To speak to some professing Christians you might get the impression they set the terms of their "personal relationship" themselves. Don't question or judge. They've prayed a certain prayer and that's that. They're now Christians. And it would be easy to assume Jesus had no say in the matter. He just accepts those who say they know Him.
And, of course, we're happy when people say they love and know Jesus. We want people to know Jesus. Sometimes the church is so happy they claim to know Jesus she doesn't want to raise any questions about the matter. We don't want to judge anybody, after all. Then we come to texts like this one. They're less analyzed because they tell the less popular story about how one comes to "know Jesus," because they do it from Jesus' side of the story. The terms are fixed and non-negotiable. They shift the emphasis in conversion from how I feel about my connection to Jesus and replace it with how Jesus understands His connection to me.
And the emphasis isn't just on my personal relationship with Jesus. To use Jesus' own terminology, its a matter of my acceptance of the terms of the new covenant with Him. That's why, as He came to the end of His earthly life, He described the atoning shedding of His blood as, "...the new covenant in my blood" (1 Corinthians 11:25).