Sayyiduna Malik bin Huwairith (may Allah be pleased with him) narrates: The Prophet (peace and blessings of Allah be upon him) said to me and my companion: "When you set out, then one of you should give the adhan and he should say the iqamah, and the one who is older among you should lead you in prayer."
Hadith Referenceصحیح ابن حبان / كتاب الصلاة / 2130
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح: ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرطهما، وانظر (1658).