Dhruva Mahārāja was cognizant of the defective nature of his own devotional service. Pure devotional service is without material form and is not covered by mental speculation or fruitive activities. Pure devotional service is therefore called ahaitukī, unmotivated. Dhruva Mahārāja knew that he had come to worship the Lord in devotional service with a motive—to get the kingdom of his father. Such an adulterated devotee can never see the Supreme Personality of Godhead face to face. He therefore felt very grateful for the causeless mercy of the Lord. The Lord is so merciful that not only does He fulfill the desires of a devotee who is driven by ignorance and desires for material benefit, but He also gives such a devotee all protection, just as a cow gives milk to a newly born calf. In the Bhagavad-gītā it is said that the Lord gives intelligence to the constantly engaged devotee so that he may gradually approach the Lord without difficulty. A devotee must be very sincere in his devotional service; then, although there may be many things wrong on the devotee's part, Kṛṣṇa will guide him and gradually elevate him to the highest position of devotional service.
The Lord is addressed herein by Dhruva Mahārāja as puruṣārtha-mūrti, the ultimate goal of life. Generally puruṣārtha is taken to mean execution of a type of religious principle or worship of God in order to get material benediction. Prayers for material benediction are intended for satisfying the senses. And when one is frustrated and cannot fully satisfy the senses in spite of all endeavor, he desires liberation, or freedom from material existence. These activities are generally called puruṣārtha. But actually the ultimate goal is to understand the Supreme Personality of Godhead. This is called pañcama-puruṣārtha, the ultimate goal of life. Lord Caitanya therefore taught us not to ask from the Supreme Personality any benediction such as material wealth, popularity or a good wife. One should simply pray to the Lord to be constantly engaged in His transcendental loving service. Dhruva Mahārāja, being cognizant of his desire for material benefit, wanted protection from the Lord so that he might not be misled or deviated from the path of devotional service by material desires.