Sahampatibrahmasutta

Suttapiṭaka · Saṁyuttanikāya · Mahāvaggasaṁyutta · Vol. 19 · Section 1048

[1048] Then Brahmā Sahampati, knowing with his own mind the reflection in the Blessed One's mind, vanished from the brahmā world and appeared before the Blessed One — just as a strong man might extend his bent arm or bend his extended arm.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.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