Persons whose austerity is meager can hardly obtain the service of the pure devotees who are progressing on the path back to the kingdom of Godhead, the Vaikuṇṭhas. Pure devotees engage one hundred percent in glorifying the Supreme Lord, who is the Lord of the demigods and the controller of all living entities.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
दुरापा ह्यल्पतपसः सेवा वैकुण्ठवर्त्मसु । यत्रोपगीयते नित्यं देवदेवो जनार्दनः
durāpā hyalpatapasaḥ sevā vaikuṇṭhavartmasu | yatropagīyate nityaṃ devadevo janārdanaḥ
SB 3.7.20