There is apparently an easy test to distinguish good schoolteachers from poor ones; ask them what they teach. Poor ones reply, 'I teach French,' or 'I teach physics' or whatever their subject is. Good ones say, 'I teach children.' The teacher here would have fallen into the second group: he taught knowledge to people. Or better, he imparted knowledge, meaning he passed over so that the people who learned from him knew the lessons for themselves.