Malik bin Huwairith (may Allah be pleased with him) narrates that the Messenger of Allah (ﷺ) commanded us: "Pray as you have seen me praying, and when the time for prayer comes, let one of you give the call to prayer (adhan), and let the eldest among you lead the prayer."
Hadith Referenceمسند الإمام الشافعي / كتاب الصلاة / 294
Hadith Takhrijاخرجہ البخاری، الاذان، باب الأذان للمسافرین اذا كانوا جماعة والاقامة: 631، ومسلم، المساجد، باب من احق بالامامة: 674۔