Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 3


इमे अङ्गिरस: सत्रमासतेऽद्य सुमेधस: ।षष्ठं षष्ठमुपेत्याह: कवे मुह्यन्ति कर्मणि ॥ ३ ॥


ime aṅgirasaḥ satramāsate ’dya sumedhasaḥṣaṣṭhaṁ ṣaṣṭham upetyāhaḥkave muhyanti karmaṇi


Nābhāga’s father said: All the descendants of Aṅgirā are now going to perform a great sacrifice, but although they are very intelligent, on every sixth day they will be bewildered in performing sacrifice and will make mistakes in their daily duties.


Nābhāga was very simple hearted. Therefore when he went to his father, the father, out of compassion for his son, suggested that as a means of livelihood Nābhāga could go to the descendants of Aṅgirā and take advantage of their misgivings in performing yajña.