Can relying on rental income for livelihood fulfill the obligatory duty to earn money as a Muslim? Or should one find a job or start a business?
Relying on rental income is permissible as far as it is enough for your livelihood expenses. If you have time and power to work, then it is good to work. You can use the extra income for your everlasting future in Aakhirah by helping helpless people.
Wassalam.