Quoting from my friend, Mark Batterson -
A few years ag I read a book by R. T. Kendall titled The Annointing. I memorized something he said because it's so true. "The greatest opposition to what God is doing today comes from those who were on the cutting edge of what God was doing yesterday."
If don't know Mark, you need to get to know him. His books are awesome. And this quote is a new favorite of mine. I pray that I will never be so enamored by the past as to forget that God is always doing anew thing.
Another great quote, "When your memories exceed your dreams, the end is near."