Then, the most merciful Supreme Personality of Godhead desired to incarnate for the three purposes He speaks of:

paritrāṇāya sādhūnāṁ vināśāya ca duṣkṛtām
dharma-saṁsthāpanārthāya sambhavāmi yuge yuge

“To deliver the pious and to annihilate the miscreants, as well as to reestablish the principles of religion, I Myself appear, millennium after millennium.” (Bhagavad-gītā 4.8)

Another reason for Him to desire to incarnate was to fulfill the cherished desires of His worshipper Daśaratha.

Therefore, He arrived on the spot. This was the time His protection was sought. It is to be concluded that He had been waiting for this opportunity for a long period of time. Indeed, it has been stated:

sarva-jño ’pi hi deveśas sadā kāruṇiko ’pi san
saṁsāra-tantra-vāhitvād rakṣāpekṣāṁ pratīkṣate

“Though omniscient and though always merciful, the Lord of the demigods waits for His protection to be sought while observing the principles of material existence.”

Viṣṇuḥ indicates that He became present because He was all-pervading.

Mahā-dyutiḥ indicates that He was endowed with a special splendor born out of His abundant delight on having obtained an opportunity to protect His saintly devotees. From this, it is understood that prior to this, His mind was distressed by seeing the wretched situation of the conditioned souls. We learn from the Śruti: sa ekākī na rameta, “He is not happy alone.”

Śaṅkha-cakra-gadā-pāṇiḥ. The Supreme Lord considers that if He were to keep these items elsewhere for protecting His devotees, when there is a need to protect them, there would be a delay in picking up those items. Therefore, He is always endowed with a conch, a disc and a mace to protect His saintly devotees. The learned authority Śrī Parāśara Bhaṭṭa has stated in this regard:

pātu praṇata-rakṣāyāṁ vilambam asahann iva
sadā pañcāyudhīṁ bibhrat sa naḥ śrī-raṅga-nāyakaḥ

“May Lord Śrī Raṅganātha protect us. He always holds His five weapons as if impatient of any delay in protecting those surrendered unto Him.”

Pīta-vāsāḥ indicates that He was fully dressed up and ready, in a hurry, to protect those who had taken shelter of Him.

Jagat-patiḥ indicates that He is the proprietor and master of the entire world, which is itself the cause for His appearance.

Upayātaḥ indicates that He came to Daśaratha’s sacrificial arena from Vaikuṇṭha.