I read this quote today in Difficulties in Mental Prayer: A New Edition of a Classic Guide to Meditaion by M. Eugene Boylan, O.C.R. I know I often have regrets about my past - the mistakes I made along the way, the sins I committed. This is a good reminder that God is the one ultimately in charge and He can, and does, bring good out of the messiness.
"To them that love God, all things work together unto good," writes St. Paul, and that includes even our sins. God has infinite power and infinite mercy. He can utilize all our past and turn it to good account.