Maggasutta

Suttapiṭaka · Saṁyuttanikāya · Mahāvaggasaṁyutta · Vol. 19 · Section 822

[822] Then, bhikkhus, Brahmā Sahampati, having known with his own mind the reflection in my mind, just as a strong man might extend his bent arm or bend his extended arm, even so vanished from the brahmā world and appeared before me. Then, bhikkhus, Brahmā Sahampati, having arranged his upper robe over one shoulder and raised his joined palms in reverence toward me, said this to me:

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 19 · Section 755 — Brahmasutta