व्यासप्रसादाच्छ्रुतवानेतद्गुह्यमहं परम्। योगं योगेश्वरात्कृष्णात्साक्षात्कथयतः स्वयम् ॥

vyāsa-prasādāch chhrutavān etad guhyam ahaṁ param yogaṁ yogeśhvarāt kṛiṣhṇāt sākṣhāt kathayataḥ svayam

By the favour of Vyâsa I listened to this secret and supreme yoga from the Lord of Yoga, Krishna Himself, speaking before mine eyes.

In plain words: Sanjaya says that by the gift of the sage Vyasa, who gave him special sight, he heard this secret, highest teaching straight from Krishna, the Lord of Yoga, as if right before his eyes.