Twenty-something, young and immature as a Christian, just out of college, I moved into a low-income apartment complex with about 75 units in sunny Orange County. As one of the only middle-class, white kids living there, I was pretty visible. What sticks out in my memory, aside from having a car dissappear from the car-port, was a gift that one of my neighbors gave me. A Korean immigrant family lived about 3 stucco doors down and I would sometimes try to say hello to their teenage son. Nobody there seemed to speak English and I didn't realize there was much of a relationship there. I certainly never witnessed about Jesus or anything. Maybe, I shared a soda or something but can't really remember anything special.
As I was moving out of the apartment and easily onto another life, a shy Korean teen approached and handed me a music CD. Somehow, he told me that my friendship was valuable to him and left me standing there with a blue WOW music cd. To this day, I'm haunted by what I could have done to befriend him and his family.
Urban ministry - just being there is a start. For some great ministry ideas check out Dallas Metro urban ministries. I am particularly interested in their Adopt-a-Block ministry.