We discuss repeatedly what it means to the individual to be able to say 'no' when refusing something away from themselves. This is an interesting subject because there are several ways we can do this, with several differing outcomes.
If for example I am struck by another person with a blow intentionally aimed at me, I have the right per se to hit back, even perhaps using more force than was given to me. Once that first hit has been initiated, then I may answer it in rebuttal. Equally so I may choose not to react at all. I am not obliged to hit back, even though I can. By being able to hit back, but not doing so, I am actually deciding to be gentle.
Little children are far from gentle. Their 'no's are also as strong as the hit of a naturally won rebuttal. In the story of Courtesy, Propriety and Decorum we have strong imagery of that individual who cannot operate outside of their limited scope. Like a child who really does not comprehend what they are dealing with, there is a destructive outcome if mere practice is all that there is as a model of behavior.
The stronger the 'I Am' is developed within the individual, the more gentle their 'no' is pronounced. It is however very definite nonetheless and completely valid for them to say and act upon.
'No' is a given within the free-will of Man - its manner of delivery is a chosen.