Sayyiduna Ibn Umar (may Allah be pleased with them both) said: When we set out from Mina (towards Arafat) with the Noble Prophet (peace and blessings be upon him), some of us were reciting the takbir and some of us were calling out the talbiyah.
Hadith Referenceسنن دارمي / من كتاب المناسك / 1914