Śrīmad-Bhāgavatam · Text 9.22.25
Who is speaking and story frame
क्षेत्रेऽप्रजस्य वै भ्रातुर्मात्रोक्तो बादरायण: ।
धृतराष्ट्रं च पाण्डुं च विदुरं चाप्यजीजनत् ॥ २५ ॥
kṣetre ’prajasya vai bhrātur
mātrokto bādarāyaṇaḥ
dhṛtarāṣṭraṁ ca pāṇḍuṁ ca
viduraṁ cāpy ajījanat
Bādarāyaṇa, Śrī Vyāsadeva, following the order of his mother, Satyavatī, begot three sons, two by the womb of Ambikā and Ambālikā, the two wives of his brother Vicitravīrya, and the third by Vicitravīrya’s maidservant. These sons were Dhṛtarāṣṭra, Pāṇḍu and Vidura.
Read Śrīla Prabhupāda's purport on Vedabase.io