By devotional service one can understand that Kṛṣṇa first of all manifests Himself as svayaṁ-rūpa, His personal form, then as tad-ekātma-rūpa, and then as āveśa-rūpa. It is in these three features that He manifests Himself in His transcendental form. The feature of svayaṁ-rūpa is the form by which Kṛṣṇa can be understood by one who may not understand His other features. In other words, the form by which Kṛṣṇa is directly understood is called svayaṁ-rūpa, or His personal form. The tad-ekātma-rūpa is that form which most resembles the svayaṁ-rūpa, but there are some differences in the bodily features. The tad-ekātma-rūpa is divided into two manifestations: the personal expansion (svāṁśa) and the pastime expansion (vilāsa). As far as the āveśa-rūpa is concerned, when Kṛṣṇa empowers some suitable living entity to represent Him, that living entity is called āveśa-rūpa or śaktyāveśa-avatāra.
The personal form of Kṛṣṇa can be divided into two: svayaṁ-rūpa and svayaṁ-prakāśa. As far as His svayaṁ-rūpa (or pastime form) is concerned, it is in that form that He remains always in Vṛndāvana with the inhabitants of Vṛndāvana. This personal form (svayaṁ-rūpa) can be further divided into the prābhava and vaibhava forms. For example, Kṛṣṇa expanded Himself in multiple forms during the rāsa dance in order to dance with each and every gopī who took part in that dance. Similarly, He expanded himself into 16,108 forms in Dvārakā when he married 16,108 wives. There are some instances of great mystics' expanding their bodily forms by the yoga process, but Kṛṣṇa did not expand Himself in that way. In Vedic history, Saubhari Ṛṣi expanded himself into eight forms by the yoga process, but those expansions were simply reflections, for Saubhari remained one. But when Kṛṣṇa manifested Himself in different forms, each and every one of them was a separate individual. When Nārada Muni visited Kṛṣṇa at His different palaces in Dvārakā, he was astonished at this, and yet Nārada is never astonished to see the expansions of a yogīs body, since he knows the trick himself.
Śrīmad-Bhāgavatam describes Nārada Muni's astonishment at seeing Kṛṣṇa's expansions in Dvārakā. Nārada wondered how the Lord was present with His queens in each and every one of His 16,108 palaces. With each queen, Kṛṣṇa Himself was in a different form, acting in different ways. In one form He was talking with His wife, in another form He was petting His children, and in another form He was performing some household duty. These different activities are conducted by the Lord when He is in His "emotional" forms, which are known as vaibhava-prakāśa expansions. Similarly, there are other unlimited expansions of Kṛṣṇa's forms, but even when they are divided or expanded without limit, they are still one and the same. There is no difference between one form and another. That is the absolute nature of the Supreme Personality of Godhead.