Anas declared that God’s messenger used to say, “Do not impose austerities on yourselves and so have God imposing austerities on you; for people have imposed austerities on themselves and God has imposed austerities on them. Their survivors are to be found in cells and monasteries.” [Then he quoted], “Monasticism, they invented it; we did not prescribe it for them.” 1
Abu Dawud transmitted it.
1 ibid, lvii, 27.