“I saw the Prophet (ﷺ) on the Day of Sacrifice, at ‘Aqabah Pillar. He went to the interior of the valley and threw seven pebbles, saying Takbir with each pebble, then he departed.”

Another chain reports a similar hadith.
Sunan Ibn Majah Book 25, Hadith 150
← Previous Hadith “When ‘Abdullah bin Mas’ud stoned ‘Aqabah Pillar, he went to the bottom of the valley and turned to face the Ka’bah, with the Pillar on his right hand side. Then he threw seven pebbles, saying the Takbir with each one. Then he said: ‘From here, by the One besides Whom there is none worthy of worship, did the one throw, to whom Surat Al-Baqarah was revealed.’”

Sunan Ibn Majah Book 25, Hadith 149 Next Hadith → It was narrated that Ibn ‘Umar stoned ‘Aqabah Pillar, but he did not stay there, and he mentioned that the Prophet (ﷺ) had done likewise.

Sunan Ibn Majah Book 25, Hadith 151