"what I'm weaker than you, and why I can not perform your job?"

I often imagine the situation when my future subordinates asked me - "what I'm weaker than you, and why I can not perform your job?".

I understand that I have to know the best answer to this question. And now it seems to me that the fundamental difference between my position and that the subordinates of my business is that - I should be able to step into the "abyss", and above all - do not fall. I have to show the way to go.

And yet, very important point.
I will not have to remember my words today, but would have to feel the need to say these words, not any other.