Hazrat Abdullah ibn Mas’ood (Radhiyallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “To seek a halaal livelihood is an obligation which is necessary after fulfilling all the Faraa’idh of Deen (Salaah, fasting,zakaat, etc.)“
Note: The primary purpose for man’s existence in this world is to worship Allah Ta’ala. However, in order for man to survive in the world, it is to a certain extent necessary for him to earn a living to sustain himself and his dependants. Hence permission has been granted to him after fulfilling all his obligations to his Creator, to see to his needs and the needs of his dependants. The seeking of a halaal livelihood being fardh in Deen as mentioned in this Hadith refers to earning to the extent of fulfilling the basic needs of oneself and one’s dependants. Seeking livelihood over and above this amount is not fardh, rather permissible.