Musannaf Ibn Abi Shaybah 7847 — The virtue of prayer

Zirr said: We used to present the copies of the Qur'an to Sayyiduna Abdullah (bin Mas'ud) (may Allah be pleased with him). A man from Thaqif asked him, "O Abu Abd al-Rahman! Which deed is the most virtuous?" He said, "Prayer; and whoever does not pray has no religion."