The Messenger of Allah ﷺ said, "Jibreel came to me and said, 'Muhammad, instruct your companions to raise their voices in the talbiyah.'"
أخبرنا إسحق بن إبراهيم قال أنبأنا سفيان عن عبد الله بن أبي بكر عن عبد الملك بن أبي بكر
عن رسول الله ﷺ قال جاءني جبريل فقال لي يا محمد مر أصحابك أن يرفعوا أصواتهم بالتلبية
[Its chain is sahih] Tirmidhi transmitted it in the chapters on Hajj, in the chapter on raising the voice with the talbiyah, hadith no. 829, and Ibn Majah in the chapters on the rites, in the chapter on raising the voice with the talbiyah, hadith no. 2922, from the hadith of Sufyan bin Uyayna through this route. He explicitly stated hearing it directly, as recorded in Humaydi, hadith no. 855 (in my edition), and it is also in al-Kubra, hadith no. 3734. Tirmidhi said, hasan sahih, and Ibn Khuzayma graded it sahih, hadith nos. 2625, 2627, as did Ibn Hibban, hadith no. 974, and others.