The Ruling on seeking Islamic Knowledge
Question :
Is a person excused for not seeking (Islamic) knowledge due to being busy with studies unconnected with Islamic knowledge, or because of work etc.?
Answer:
The acquisition of Islamic knowledge is Fardh Kifayah meaning that if enough people do so, it becomes a Sunnah for the rest of them. But the acquisition of knowledge could be Fardh 'Ain for all of the people that is, if a person wanted to worship Allah through a certain act of worship, it would be incumbent upon him to know how to perform this act of worship to Allah. In view of this, if one were to occupy himself with something to the neglect of seeking Islamic knowledge, he and his family would be protected by learning what was sufficient for them, so long as they maintained the acts of worship which are an obligation upon them. We hold that this is excused and there is no objection to it, but he must learn as much Islamic law as is possible for him.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 1 Pages 370-371