Happiness, the satisfaction of all our desires, is too indeterminate to be a workable guide. Good will isn't the sole and complete good, but it's the highest good and the condition of the worthiness to be happy. The complete good is happiness combined with good will. Hypothetical and Categorical Imperatives Rationality has its own objective laws. Such imperatives rest on grounds that are valid for every rational being as such.
Categorical imperatives are difficult to understand but clear in their content.
Morality and Freedom Kant connects morality with freedom. Hence, to be free is to be moral. So freedom and morality are ultimately the same mystery. We know that we're free by knowing that we have duties. Acting morally has supreme moral worth because through it we participate in a higher order of existence.