Musnad Ahmad 31:154

Mansur ibn Salamah narrated to us, Abu al-Ashhab al-Utaridi narrated to us, from Abu Nadrah, from Abu Sa’id al-Khudri, from the Prophet, peace and blessings of Allah be upon him, that he said: "Follow me, and those after you will follow you. For there will continue to be people who hold back, until Allah, the Almighty and Majestic, holds them back."