A person should always be soft like a reed and not hard like a cedar. A reed lives in places of water, and its trunk changes, and it has many roots. If all of the winds of the world were to blow upon it, it will not budge. Instead it comes and goes with them. When the wind stops blowing the reed stands in its place.
A cedar does not stand near water, and its trunk does not change, and it as few roots. If all of the winds in the world were to blow upon it, it does not budge. However, if a southern wind blows, it is uprooted and turned over on its face. (Sefer Haagadah 554 after Sanhedrin 105b; Taanit 20a)
Rabbi Eliezer the pitch-man said one should not be like the top door-post which may not be touched by Human hands. Instead, one should be like the bottom door step, upon which everybody walks. If in the end the whole building collapses the bottom door step stays in its place. (Fathers of Rabi Natan, Chapter 26)