Mahmud bin Ghaylan محمود بن غيلان العدوي مولاهم أبو أحمد · The Book of Leading the Prayer (Al-Imamah)

"Come forward and follow me, and let those who are behind you follow your lead. If people continue to lag behind, Allah, the Mighty and Sublime, will put them back."

"I prayed with the Messenger of Allah (ﷺ)and I stood on his left. He took hold of me with his left hand and made me stand on his right."