JMNT(i)
39 "Now you normally know this by personal experience (or, as an imperative: But be coming to experientially know this), that if the householder had seen, or by foresight had perceived so as to be aware, at what hour the thief is proceeding in coming, he would stay awake and be watchful – and thus not allow his house [wall] to be dug through (= let his house be broken into).