A study of the Lachish letters (ostraca) that goes beyond treating conventional formulae as simply epistolary phenomena or scribal preference shows that such language, along with other forms of language expressed in the letters, reflects a culture of high politeness. However, this culture is not restrictive. The senders also feel free to express their opinion and even criticise the recipient at times, with a corresponding reduction in respectful language. Such adjustment of language use to topic and/or emotion explains the variation in both conventional and other forms of polite language. When compared to biblical narrative and prayer, the letters affirm the biblical portrayal of social relationships. That is, the biblical portrayal of generally high politeness to a social superior or deity yet freedom to express opinion and criticism, along with the reduction in politeness that naturally occurs, with it reflects social reality of the time.