SB 1.9 - Bhīṣma's worshipable form
Bhīṣma desired the Lord as a charioteer. He had attained Him, who was the charioteer of Arjuna, holding the whip and bridle in His hands, and who was now appearing in Bhīṣma’s heart. But the charioteer is not the Lord in the heart. Because Kṛṣṇa, the charioteer, had already entered and pervaded his heart completely by practice, it was not possible for Paramātmā to enter. Though He appeared to Bhīṣma’s eyes in this form at the time of battle, even before the battle Kṛṣṇa was already in his heart because of his spontaneous desire. Kṛṣṇa is unborn because He had always been visible to Bhīṣma. The Supreme Lord alone situated in the heart ordains good fortune or misfortune of the jīvas. He is situated in the hearts of all jīvas, who create their own bodies.
Bhīṣma knew the charioteer Kṛṣṇa and the four-handed form in Dvārakā were not different, just like the one sun appears to be many situated above each person’s head. Though Kṛṣṇa appeared in Bhīṣma’s heart and in the hearts of Yudhiṣṭhira, Vasudeva, Uddhava, Nanda and the gopīs with various degrees of prema with different pastimes for each, Bhīṣma knew that this was one Kṛṣṇa only. But Bhīṣma could never give up his natural attachment to the form of Kṛṣṇa as the charioteer. The worshipable object of Bhīṣma is Kṛṣṇa as Pārtha-sārathi, and that of the gopīs is the same Kṛṣṇa as Śyāmasundara. Sometimes the foolish think that the two are different personalities.