Instrumental Case in the Meaning of Profession or Occupation

Did you know that we use the verbs быть (to be), стать (to become) and работать (to work) with the Instrumental case?

For example,

Я буду врачом. I will be a doctor.

Он станет учителем. He will become a teacher.

Мы работаем программистами. We work as computer progremmers.