Whatever work is done here in this life for the satisfaction of the mission of the Lord is called bhakti-yoga, or transcendental loving service to the Lord, and what is called knowledge becomes a concomitant factor.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
यदत्र क्रियते कर्म भगवत्परितोषणम् । ज्ञानं यत्तदधीनं हि भक्तियोगसमन्वितम्
yadatra kriyate karma bhagavatparitoṣaṇam | jñānaṃ yattadadhīnaṃ hi bhaktiyogasamanvitam
SB 1.5.35