My dear Vyāsa, even though a devotee of Lord Kṛṣṇa sometimes falls down somehow or other, he certainly does not undergo material existence like others [fruitive workers, etc.] because a person who has once relished the taste of the lotus feet of the Lord can do nothing but remember that ecstasy again and again.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
न वै जनो जातु कथञ्चनाव्रजे- न्मुकुन्दसेव्यन्यवदङ्ग संसृतिम् । स्मरन् मुकुन्दाङ्घ्र्युपगूहनं पुन- र्विहातुमिच्छेन्न रसग्रहो यतः
na vai jano jātu kathañcanāvraje- nmukundasevyanyavadaṅga saṃsṛtim | smaran mukundāṅghryupagūhanaṃ puna- rvihātumicchenna rasagraho yataḥ
SB 1.5.19