It is narrated from Sayyiduna Malik bin al-Huwayrith (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When you are with your companion, give the adhan and the iqamah, and let the elder of you two lead the prayer."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16687