maharsayah sapta purve
catvaro manavas tatha
mad-bhava manasa jata
yesham loka imah prajah
The seven great sages and before them the four other great sages and the Manus [progenitors of mankind] come from Me, born from My mind, and all the living beings populating the various planets descend from them.
Commentary by Srila Prabhupada
The Lord is giving a genealogical synopsis of the universal population. Brahma is the original creature born out of the energy of the Supreme Lord, who is known as Hiranyagarbha. And from Brahma all the seven great sages, and before them four other great sages, named Sanaka, Sananda, Sanatana and Sanat-kumara, and the Manus, are manifested. All these twenty-five great sages are known as the patriarchs of the living entities all over the universe. There are innumerable universes and innumerable planets within each universe, and each planet is full of population of different varieties. All of them are born of these twenty-five patriarchs. Brahma underwent penance for one thousand years of the demigods before he realized by the grace of Krishna how to create. Then from Brahma came Sanaka, Sananda, Sanatana and Sanat-kumara, then Rudra, and then the seven sages, and in this way all the brahmanas and kshatriyas are born out of the energy of the Supreme Personality of Godhead. Brahma is known as Pitamaha, the grandfather, and Krishna is known as Prapitamaha, the father of the grandfather. That is stated in the Eleventh Chapter of the Bhagavad-gita (11.39).
Commentary by Sri Visvanatha Cakravarti Thakur
Not having mentioned that intelligence, knowledge and non-bewilderment cannot give real knowledge of the Lord, the Lord in this verse states that these things cannot give true knowledge of the Lord.
The seven great sages beginning with Marici, the four Kumaras such as Sanaka, and the fourteen Manus beginning with Svayambhuva, take birth from me in the form of Hiranyagarbha (Brahma). They arose from my mind. The brahmanas and others exist as the offspring, sons and grandsons, or students, and students of students of the seven sages, the four Kumaras and the Manus.