As now, so then

I am reading a book right now entitled Not A Fan by Kyle Idleman.  In this book, Kyle mentions the "as now, so then" principle.  He states this is a principle of human behavior that explains why we should not put off tomorrow what we can do today.  However we handle situations now will be how we handle them in the future.  That is why putting something off leads to the "something" never getting done.  He states, "the vast majority of the time, the decision you make today will be the decision you make tomorrow."