Running Slow to Run Fast

When I went on my short run today I met two boys, probably high school kinds, at the water fountain. I asked them what distance they were doing and one of them replied 20 miles.I asked if they were preparing for the marathon and apparently one of them was.
It reminded me of my first marathon. I had trained very hard to run my first marathon in 1988 (Chicago marathon), but the marathon was canceled that year and I ran the half marathon that was organized that year. The following year, 1989, I ran my first marathon. I consciously ran a 'slow' first half because I wanted to be sure I had 'enough' left in the tank to finish. I did hit the wall, but survived and finished the marathon in 3:23 or so.
It does help to run a slower pace in the beginning when the temptation is to run fast. One can put on a stronger second half and pass many people. A similar example holds for life in general- it helps to slow down in order to go fast.