1 John 4:8, 1 Corinthians 13:4, Exodus 34:14
But what exactly does that mean? A relationship has at the least, two people. Unless a "personal" relationship is akin to the way a stalker feels about his victim. And since I'm hard-pressed to find a theist who believes their god is a physical person, it seems like the latter is the direction one has to go in.
In an actual relationship between two people, each party grows, changes, and effects one another. Each participating member benefits from the others' involvement. It is possible to be in a relationship and not contribute to it, and those relationships don't last long. I realize that from a theistic standpoint, one can hope to change and grow "in God" or "in Jesus" or "in Minerva", but that really only proves the case for a one-sided relationship.
What can a changeless, all-powerful, all-knowing god hope to gain from a relationship? Gaining something itself implies a lack of something in the first place. If the god knows all in the future, no excitement or surprise can come, so there's no benefit there. Such a deity can't change, can't grow, can't be effected.
I realize at best I'm arguing for deism here, and I don't intend to. Let's turn the focus back to the idea that each worshiper has their own "personal relationship" with God. I don't think I can do a better job of illustrating the flaws with this idea than what has already been done by YouTube user NonStampCollector:
Put simply: there wouldn't be so many differing views on the wishes of a (supposedly) singular entity if all those who profess to engage in a personal relationship with said entity actually did so.
Happy Valentine's Day everyone. Find someone -- a real person -- with whom you have an actual, personal relationship with, and spend some time with them.