Those were the words that I grew up with at home, not verbally, but in our actions at going anywhere. Then in high school they were the exact words my high school coach used. I don't know if that being beaten into me from such a young age or not, but I think being on time, actually being early, is one of the most important things you can do as a player/coach/person.
Telling someone that you will be somewhere at a certain time is giving your word. If you are late, then in some way you are being less than truthful about how important you think their time is. Being told to be somewhere at a certain time is an act of responsibility to your employer, to the team, to anything you are going to.
It may be very easy for me as I have rarely had a problem with time and for something it just seems to be an issue... Often it is because that person is doing too many things or has lost track of time, but those are excuses often not reasons. I do realize that there are sometimes things we cannot control which causes us to be late, but I would bet that a large amount of those things we cannot control could have been contained by our actions.
Being on time is important. If that is something that you or those in power can know they rely upon with you, it is a great building block for success. Be on time!!! Better yet....be early!