abase oneself by doing (sth.)

abase vt.:
1. make...humble or embarrassed
Betraying his close friend abased himself among his friends.

2. make status or identity etc. reduced
Nobody doesn't refuse to abase himself in the presence of other.
He would not abase himself by showing any fear.
The boss was not willing to abase himself before the staff.

abase n.: belittling, humility or humiliation; or one who abases others.