In this verse the word hṛdaya indicates the heart, which is also called uraḥ, the chest. The heart is situated within the chest, and although instrumentally the son is born with the aid of the genitals, he is actually born from within the heart. According to the heart's situation. the semen takes the form of a body. Therefore according to the Vedic system, when one begets a child his heart should be purified through the ritualistic ceremony known as garbhādhāna. Ṛṣabhadeva's heart was always uncontaminated and spiritual. Consequently all the sons born from the heart of Ṛṣabhadeva were spiritually inclined. Nonetheless. Ṛṣabhadeva suggested that His eldest son was superior, and He advised the others to serve him. All the brothers of Bharata Mahārāja were advised by Ṛṣabhadeva to adhere to Bharata's service. The question may be asked why one should be attached to family members, for in the beginning it was advised that one should not be attached to home and family. However, it is also advised, mahīyasām pāda-rajo-'bhiṣeka—one has to serve the mahīyān, one who is very spiritually advanced. Mahat-sevāṁ dvāram āhur vimukteḥ: (SB 5.5.2) by serving the mahat, the exalted devotee, one's path for liberation is open. The family of Ṛṣabhadeva should not be compared to an ordinary materialistic family. Bharata Mahārāja, Ṛṣabhadeva's eldest son, was specifically very exalted. For this reason the other sons were advised to serve him for his pleasure. That was to be their duty.
The Supreme Lord was advising Bharata Mahārāja to be the chief ruler of the planet. This is the real plan of the Supreme Lord. In the Battle of Kurukṣetra, we find that Lord Kṛṣṇa wanted Mahārāja Yudhiṣṭhira to be the supreme emperor of this planet. He never wanted Duryodhana to take the post. As stated in the previous verse, Lord Ṛṣabhadeva's heart is hṛdayaṁ yatra dharmaḥ. The characteristic dharma is also explained in Bhagavad-gītā: surrender unto the Supreme Personality of Godhead. To protect dharma (paritrāṇāya sādhūnām (BG 4.8)), the Lord always wants the ruler of the earth to be a devotee. Then everything goes on nicely for the benefit of everyone. As soon as a demon rules the earth, everything becomes chaotic. At the present moment, the world is inclined toward the democratic process, but the people in general are all contaminated by the modes of passion and ignorance. Consequently they cannot select the right person to head the government. The president is selected by the votes of ignorant śūdras; therefore another śūdra is elected, and immediately the entire government becomes polluted. If people strictly followed the principles of Bhagavad-gītā, they would elect a person who is the Lord's devotee. Then automatically there would be good government. Ṛṣabhadeva therefore recommended Bharata Mahārāja as the emperor of this planet. Serving a devotee means serving the Supreme Lord, for a devotee always represents the Lord. When a devotee is in charge, the government is always congenial and beneficial for everyone.