Consider marriage. A relationship founded on love, is it not? But it is also governed by rules. Even if the rules are never stated, they are nonetheless present.
When we first married, I remember announcing to my Sara one night that I was going to go out and do something with my brother. That didn't play well, and that's when I discovered an important rule: Now married, my schedule had to take into consideration my wife as well myself.
And there are other rules. Some were spelled out in our wedding vows.
Of course, sometimes there are infractions of these rules, and both apologizing and forgiveness are called for, but in order to remain in one another's love, the rules are held to.
To me this helps to understand better Jesus' words in John 15:9-10:
"As the Father has loved me, so have I loved you. Now remain in my love. If you obey my commands, you will remain in my love, just as I have obeyed my Father's commands and remain in his love." (NIV)
It sounds like, "I will love you as long as you obey me, but you screw up, and I'm dropping you like a hot potato."
But what is meant is, "I love you, profoundly, deeply. You know how much the Father loves me? That's how much I love you. Remain in my love. Follow the rules of our relationship that we might have a rich and fulfilling communion forever."