smaran muktva kalevaram
yah prayati sa mad-bhavam
yati nasty atra samsayah
Bhagavad Gita: Pure devotional Service is the best (Text 17 Chapter 7)]
sri-bhagavan uvaca
Tesam jnani nitya-yukta
eka-bhaktir visisyate
priyo hi jnanino ' tyartham
aham sa ca mama priyah
(Knowledge of the Absolute, Text 17 Chapter 7)
Meaning: Of these, the one who is in full knowledge and who is always engaged in pure devotional service is the best. For I am very dear to him, and he is dear to Me.
Bhagavad Gita: Pure devotional Service is the best, Knowlege of the Absolute (Text 17 Chapter 7)]
sri-bhagavan uvaca
Catur-vidha bhajante mam
Janah sukrtino 'rjuna
arto jijnasur artharthi
jnani ca bharatarsabha
(Knowledge of the Absolute, Text 16 Chapter 7)
Meaning: O best among the Bharatas, four kinds of pious men begin to render devotional service unto Me-the distressed, the desirer of wealth, the inquisitive, and he who is searching for knowledge of the Absolute.
*** One should render transcendental loving service to the Supreme Lord Krsna favorably and without desire for material profit or gain through fruitive activities or philosophical speculation. That is called pure devotional service.
Bhagavad Gita: Pure devotional Service (Text 16 Chapter 7)]