It is permissible for a Muslim to employ a kaafir servant subject to certain conditions which include the following:
He should not introduce anything impure (naajis) into the food or clothing of the Muslim.
He should not cook for him anything that Muslims are forbidden to eat, such as pork.
Employing this servant should not cause any fitnah (temptation) with regard to matters of religion, such as admiring Christianity or the Muslim children being influenced by the rituals of kufr which this servant may practise.
There should be no risk of being tempted by him or her, or of committing haraam actions with him or her, as may happen if the female Christian servant is uncovered in front of the Muslim head of the household or his sons, or the Muslim wife of the head of the household may be tempted by a servant or driver.
Such a servant should not be employed in the Arabian Peninsula where it is haraam for the kuffaar to settle.
The servant should not be mistreated or his rights denied; one of the bad consequences of that is that it puts him off Islam.
The Muslim must strive to employ Muslims because they are less evil, in general, than the kuffaar, and less likely to commit haraam actions that go against sharee’ah or to make others commit them. If a Muslim does have a kaafir servant, he should strive to call him to Islam and to guide him.
The evidence that it is permissible to employ a trustworthy kaafir servant and call him to Islam is the hadeeth narrated by al-Bukhaari (1356) from Anas (may Allaah be pleased with him) who said: “A Jewish boy used to serve the Prophet (peace and blessings of Allaah be upon him), and he fell sick. The Prophet (peace and blessings of Allaah be upon him) went and visited him. He sat by his head and said, ‘Enter Islam.’ The boy looked at his father, who was present. (His father) said, ‘Obey Abu’l-Qaasim (peace and blessings of Allaah be upon him).’ So he entered Islam and the Prophet (peace and blessings of Allaah be upon him) left saying, ‘Praise be to Allaah Who has saved him from the Fire.’”
And Allaah is the Source of strength.