Śrīla Bhakti Rakṣak Śrīdhar Dev-Goswāmī Mahārāj describes the spirit of pure devotion given in Śrīmad Bhāgavatam.
In the beginning, the Bhāgavata announces, “What is bhakti? What is dharma? What is the highest dharma? What is the prime duty, the supreme duty of us all?”
sa vai puṁsāṁ paro dharmo yato bhaktir adhokṣaje
ahaituky apratihatā yayātmā suprasīdati
(Śrīmad Bhāgavatam: 1.2.6)
Our highest duty is submission to Adhokṣaja, the unseen, He who is indistinguishable by our senses in our present position.
Ahaitukī: that submission is causeless; it does not have any expectation of any reaction or any benefit. It has no reason and rhyme but is an eternal flow that is apratihatā: irresistible and autocratic. The most fundamental flow of this whole world, both gross and subtle, is so deep that it cannot be stopped or challenged by anything. It is automatic and gives its own explanation; it is not responsible for providing an explanation to anything else. No cause or effect can be traced in it; it is an infinite flow, an automatic wave, nirguṇa, and is the deepest foundation of all existence—automatic, causeless, and irresistible. To join that flow is our highest dharma announces the Bhāgavata.
sa vai puṁsāṁ paro dharmo yato bhaktir adhokṣaje
(Śrīmad Bhāgavatam: 1.2.6)
The Infinite is undistinguishable, unseen, imperceptible, at your present position and has the deepest flow that is irresistible and automatic. Your highest duty is to connect yourself with that, to join that. Think about it. It is absolute good, absolute beauty, absolute love, absolute charm, absolute mercy—whatever good you can conceive of, that flow is the root of it. So, connect with that deepest flow in the universe and not any superficial external thing: exploitation or renunciation. Above them is submission. As much as your realisation deepens, you will find such things.
sa vai puṁsāṁ paro dharmo yato bhaktir adhokṣaje
ahaituky apratihatā yayātmā suprasīdati
(Śrīmad Bhāgavatam: 1.2.6)
Direct yourself towards the undistinguishable Infinite. Try to connect with Him, that irresistible plane of the whole. As much as you will be able to make progress, you will have experience of that, and that experience will belittle your experience of the mundane. Paraṁ dṛṣṭvā nivartante (Bg: 2.69): the charm of all these base and outer things will disappear. You will find newer and newer charm above, and your attraction for gross mundane things will vanish. As you are able to realise higher things, your attraction for lower things will disappear; it will vanish automatically.
Source
Spoken 3 July 1982.