Sage Narad describes the highest ideal of service and love as it pertains to the Gopis in this verse of the Narad Bhakti Darshan:

Nastyeva Tasmin Tatsukha Sukhitvam

One of the most important aspects of Bhakti is to be happy in the happiness of God and Guru – to serve them according to their desire.

Let us take the example of the Gopis.

Vrindavan and Mathura are 6 miles apart. Yet when Shri Krishna left for Mathura, the Gopis did not go to see him, despite the terrible pain of separation that they felt. Their reasoning was such:

“If Shri Krishna wanted to see us he would have come here. We cannot go to see him in Mathura for our own happiness.”

There is nothing wrong with turning our desires towards God and Guru in service. However, we must be careful to note that even our service is rendered according to what they ask of us and not how we desire to serve them. For example, we all have our talents with which we desire to serve the divine. However, having a specific talent does not guarantee that we will always be able to use it in their service.

If the Guru calls upon us to do something other than what makes us happy or what comes naturally to us, we must joyfully do it without question exactly in the way he wants us to do it.

Let us say the Guru asks us for water and we say, “Guruji, I desire to give you a rasgulla.” Does this constitute service? No. A servant fulfills his master’s desire. When we desire something from the Guru, we are no longer his servants; he becomes our servant!

Shree Maharajji explains the various categories of servants as below:

One who sacrifices body, mind, and wealth to the Guru without being asked is a servant of the highest order.
Next in line are those who joyfully execute the Guru’s instruction upon being asked to do so, without applying their intellect.
Then there are those who serve the Guru with reluctance. They fall in the third category.
Last of all are those who do not serve the Guru, even when the Guru asks them to serve. Such disobedience results in a naamaaparaadh (spiritual transgression), since it offends the Guru, who is a God realized saint and thereby dear to God. The Guru can forgive offenses against God; however, God cannot forgive offenses against the Guru. There is no penance for a mortal sin such as naamaaparaadh.
We must understand that questioning the instruction of the Guru or any of his actions, no matter how peculiar, also results in a namaaparaadh and is the opposite of service. The only motivation behind any act of the Guru is to shower grace. When we have taken shelter of the Guru, we must always think positively of him and allow his superior divine intellect powered by Yogmaya to guide our mind, instead of letting our own Mayic intellect control the mind. This is the first out of the six aspects of surrender:

“Anukulasya sankalpaha”

We are ready to give our lives for God; however our intellect questions the only person who can lead us to him – the Guru.

A doctor can succeed in treating us only if we listen to his advice. If he asks us to drink a teaspoon of medicine, and we instead consume the whole bottle, we will pay with our lives.

The Guru is like this doctor, without whose grace we cannot become enlightened and gain our freedom from Maya.

When Arjun surrendered to Shri Krishna, he accepted Shri Krishna as the Guru and requested guidance. If he had accepted him as God, Lord Krishna would have redirected him to a Guru, since the spiritual path can only be followed under the guidance of a Guru. We cannot directly serve God until we are perfect, therefore we must accept the Guru who is a God realized saint as a form of God and serve him by fully surrendering our intellect. The perfection of this intellectual and mental surrender defines service.