One must do one’s duty.
It is she who has taught me to do my duty with full faith in God.
We should discipline ourselves and should discharge our duty for the country.
I believe in doing my duty.
One should do one’s duty.
Everybody should perform his duty honestly and efficiently.
He performs his duty diligently.
Two head constables were suspended when they were checking vehicles while they were off duty.
His duty is very hard.