Musnad Ahmad 1013:81

Yahya ibn Ishaq narrated to us, Ibn Lahi'ah informed us, from Bakr ibn Sawadah, from Sahl ibn Sa'd al-Ansari, from the Prophet, peace and blessings of Allah be upon him, who said: "By the One in whose hand is my soul, you will certainly follow the ways of those who were before you, measure for measure."