When Lord Viṣṇu appeared in the great arena of sacrifice at the time when King Pṛthu was performing a great sacrifice (aśvamedha), He predicted that the Kumāras would very soon come and advise the King. Therefore Pṛthu Mahārāja remembered the causeless mercy of the Lord and thus welcomed the arrival of the Kumāras, who were fulfilling the Lord's prediction. In other words, when the Lord makes a prediction, He fulfills that prediction through some of His devotees. Similarly, Lord Caitanya Mahāprabhu predicted that both His glorious names and the Hare Kṛṣṇa mahā-mantra would be broadcast in all the towns and villages of the world. Śrīla Bhaktivinoda Ṭhākura and Śrīla Bhaktisiddhānta Sarasvatī Prabhupāda desired to fulfill this great prediction, and we are following in their footsteps.
Regarding His devotees, Lord Kṛṣṇa told Arjuna, kaunteya pratijānīhi na me bhaktaḥ praṇaśyati: "O son of Kuntī, declare it boldly that My devotee will never perish." (BG 9.31) The point is that the Lord Himself could declare such things, but it was His desire to make the declaration through Arjuna and thus doubly assure that His promise would never be broken. The Lord Himself promises, and His confidential devotees execute the promise. The Lord makes so many promises for the benefit of suffering humanity. Although the Lord is very compassionate upon suffering humanity, human beings are generally not very anxious to serve Him. The relationship is something like that between the father and the son; the father is always anxious for the welfare of the son, even though the son forgets or neglects the father. The word anukampinā is significant; the Lord is so compassionate upon the living entities that He comes Himself into this world in order to benefit fallen souls.
- yadā yadā hi dharmasya
- glānir bhavati bhārata
- abhyutthānam adharmasya
- tadātmānaṁ sṛjāmy aham
"Whenever and wherever there is a decline in religious practice, O descendant of Bharata, and a predominant rise of irreligion—at that time I descend Myself." (BG 4.7)
Thus it is out of compassion that the Lord appears in His different forms. Lord Śrī Kṛṣṇa appeared on this planet out of compassion for fallen souls; Lord Buddha appeared out of compassion for the poor animals who were being killed by the demons; Lord Nṛsiṁhadeva appeared out of compassion for Prahlāda Mahārāja. The conclusion is that the Lord is so compassionate upon the fallen souls within this material world that He comes Himself or sends His devotees and His servants to fulfill His desire to have all the fallen souls come back home, back to Godhead. Thus Lord Śrī Kṛṣṇa instructed Bhagavad-gītā to Arjuna for the benefit of the entire human society. Intelligent men should therefore seriously consider this Kṛṣṇa consciousness movement and fully utilize the instructions of Bhagavad-gītā as preached without adulteration by His pure devotees.