What is the history of the concept of a "personal relationship with Jesus"?

It is common these days to hear questions like: > Do you have a personal relationship with Jesus? Or... > The most important thing is your personal relationship with Jesus. The Bible never uses this phrase. Jesus certainly had personal relationships with his disciples, but after his death, Paul never tells the churches in Corinth or Rome that they need better "personal relationships with Jesus." The other epistles don't talk about ways to "strengthen" that "personal relationship," etc. How long has a "personal relationship" with Jesus been talked about in Christian culture? Where did this **term and related language originate**, and what is its history? **EDIT** Please note I'm not specifically looking for Biblical references to support this concept (although that could certainly be part of a good answer!) I'm asking about the cultural history of this concept. And while I can appreciate that even Jesus made statements that can be easily interpreted as supporting a personal relationship, he definitely did not emphasize this aspect of Christian culture. When, where, how did the concept of a "personal relationship with Jesus" enter Christian culture as a prominent theme?