Sunan Ibn Majah
1280
Sahih+3

It was narrated from ‘Aishah that the Messenger of Allah (ﷺ) said the Takbir seven and five times in (the prayer for ‘Eid) Fitr and Adha, apart from the Takbir for Ruku’ (bowing)

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi