As near as I can recollect†, I was running pretty hard and not feeling very good about it. I was in the middle of my marathon training and my notes say that I ran "19 long miles/ 30.5Km". The PBGs', in their various ways suggested that I "Dig deep". And, as is usually the case, the dig deep message applied to other areas besides my aching calves.
They said, "Dig deep in your running for that is the only way to improve your conditioning and attain your goals"
"Dig deep in your quest" to listen to the needs of others around you and respond in a Christian way. The surface is there for scratching because most of the truly pivotal stuff is not displayed on the surface.
"Dig deep in your personal relationships" for you never know what lies beneath the layers you are already familiar with.
"Dig deep into spirituality" for there will always be depths that have never been plumbed and mystery waiting to be enlightened.
†Originally experienced July 10, 2004 so these thoughts are not as freshly squeezed as they aught to be. It had great punch when I lived it but may seem more like pressed leaves in retrospect.