3 miles tonight

I logged 3 miles tonight on the trail behind our house. I ran it in 28:40 which is sort of slow, but I am starting somewhere. I wondered as I was running, where does endurance come from? Is it a by by-product of something inside of us of our own doing. Is it possible that God gives some people more endurance than others? I wondered that. I have always believed when it came to running that I wasn't born to run, because of my height and flat feet. I would just love to learn to run.