She was "diligent in business," but this did not preclude her being "fervent in spirit."
The frog is a diligent songster, having a good voice but no ear.
Of what is know as Elizabethean literature he has been a diligent student.
Thus shall I be diligent to serve your Wisdoms in all humility.
Diligent enquiry there, in likely and unlikely places, proved fruitless.