Śrīmad-Bhāgavatam · Text 11.13.18
Who is speaking and story frame
श्रीभगवानुवाच
एवं पृष्टो महादेव: स्वयम्भूर्भूतभावन: ।
ध्यायमान: प्रश्नबीजं नाभ्यपद्यत कर्मधी: ॥ १८ ॥
śrī-bhagavān uvāca
evaṁ pṛṣṭo mahā-devaḥ
svayambhūr bhūta-bhāvanaḥ
dhyāyamānaḥ praśna-bījaṁ
nābhyapadyata karma-dhīḥ
The Supreme Personality of Godhead said: My dear Uddhava, Brahmā himself, who is born directly from the body of the Lord and who is the creator of all living entities within the material world, being the best of the demigods, seriously contemplated the question of his sons headed by Sanaka. The intelligence of Brahmā, however, was affected by his own activities of creation, and thus he could not discover the essential answer to this question.
Read the purport on Vedabase.ioFrom Canto 10, chapter 14 onward, the translation and purports were completed by Śrīla Prabhupāda's disciples after his departure, and published by the Bhaktivedanta Book Trust.