Sayyiduna Malik bin al-Huwayrith (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "When the time of prayer comes, give the call to prayer (adhan) and the iqamah, and let the elder of you two lead the prayer."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4998