Śrīmad-Bhāgavatam · Text 5.24.21
Who is speaking and story frame
तद्भक्तानामात्मवतां सर्वेषामात्मन्यात्मद आत्मतयैव ॥ २१ ॥
tad bhaktānām ātmavatāṁ sarveṣām ātmany ātmada ātmatayaiva.
The Supreme Personality of Godhead, who is situated in everyone’s heart as the Supersoul, sells Himself to His devotees such as Nārada Muni. In other words, the Lord gives pure love to such devotees and gives Himself to those who love Him purely. Great, self-realized mystic yogīs such as the four Kumāras also derive great transcendental bliss from realizing the Supersoul within themselves.
Read Śrīla Prabhupāda's purport on Vedabase.io