Musnad Ahmad 833:2

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Khalid, from Abu Qilabah, from Malik ibn al-Huwayrith—and he is Abu Sulayman—that they came to the Prophet, may Allah bless him and grant him peace, he and a companion of his, or two companions of his. One of them said—Ayyub or Khalid [was unsure] regarding "two companions of his"—so he said to them: "When the prayer time arrives, then give the adhan and the iqamah, and let the oldest of you lead you in prayer, and pray as you see me praying."