Parsha Vayeira - Beresheit - Chapter 18 - Verses 14 - 15.
Sarah did not know she laughed inside.
Knowing who you really are and what unique gifts Hashem gave you is our purpose in life. Very often people do not see themselves. They don’t begin to understand what they are doing. Sometimes the reason is fear.
There are 2 ways to find out who you really are. One way is to pay attention to the outer messages happening in your life. Listen to what the world is saying to you and find the kernel of truth from them so you can learn from them. The other way is to pay attention to the inner messages. Look inside yourself. You can't build on your great talents and abilities that Hashem gave you if you really don’t know who you are.