A round-about way of saying you need to "analyze; then design". He could have just as well said "model" instead of abstraction and more people would have understood what he was talking about. ERD diagrams, UML diagrams, etc. are all "models" / abstractions to help create the "final" abstraction (of some process) in code.
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I