Bhagavad Gita Verse 18.24

परन्तु जो कर्म बहुत परिश्रम से युक्त्त होता है तथा भोगों को चाहने वाले पुरुष द्वारा या अहंकार युक्त्त पुरुष द्वारा किया जाता है, वह कर्म राजस कहा गया है ।

But when any task is completed with selfish desires in mind, looked upon as an effort and nothing more, looked upon as if it was a great sacrifice to have completed a task, this type of work is impure and only performed by Rajas-natured people.