Musannaf Ibn Abi Shayba 33:831

Sharik narrated to us, from Yahya ibn Sa'id, from Sa'id ibn al-Musayyib, who said: Mu'adh said: "If there were two men, one of them charging on high-quality horses in the way of Allah, and the other remembering Allah, the latter would be greater—or better—in reward," meaning the one who remembers (Allah).