One who has forsaken his material occupations to engage in the devotional service of the Lord may sometimes fall down while in an immature stage, yet there is no danger of his being unsuccessful. On the other hand, a nondevotee, though fully engaged in occupational duties, does not gain anything.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
त्यक्त्वा स्वधर्मं चरणाम्बुजं हरे- र्भजन्नपक्वोऽथ पतेत्ततो यदि । यत्र क्व वाभद्रमभूदमुष्य किं को वार्थ आप्तोऽभजतां स्वधर्मतः
tyaktvā svadharmaṃ caraṇāmbujaṃ hare- rbhajannapakvo'tha patettato yadi | yatra kva vābhadramabhūdamuṣya kiṃ ko vārtha āpto'bhajatāṃ svadharmataḥ
SB 1.5.17