One verse

Srimad Bhagavatam 7.10.5

7.10.5

आशासानो न वै भृत्य: स्वामिन्याशिष आत्मन: । न स्वामी भृत्यत: स्वाम्यमिच्छन्यो राति चाशिष: ॥ ५ ॥

asasano na vai bhrtyah svaminy asisa atmanah na svami bhrtyatah svamyam icchan yo rati casisah

asasanah
a person who desires (in exchange for service)
na
not
vai
indeed
bhrtyah
a qualified servant or pure devotee of the Lord
svamini
from the master
asisah
material benefit
atmanah
for personal sense gratification
na
nor
svami
the master
bhrtyatah
from the servant
svamyam
the prestigious position of being the master
icchan
desiring
yah
any such master who
rati
bestows
ca
also
asisah
material profit

A servant who desires material profits from his master is certainly not a qualified servant or pure devotee. Similarly, a master who bestows benedictions upon his servant because of a desire to maintain a prestigious position as master is also not a pure master.