Motivation vs Discipline

There are 2 key terms that are in a tight race down the stretch when it comes to growth; when it comes to getting better; when it comes to personal development.  I'm not sure which came first, and I'm not sure which is more important. No, not the chicken or the egg. Im talking about motivation and discipline. Or, is it discipline and motivation. Either way, they are 2 words that, when combined, can make you unstoppable. Lock In.