‘Social trias’ (stranger, orphan, widow), as personae miserae, has been the subject of social controversy for a long time in the ancient Near East. It was not easy in ancient society to understand the ‘Social Trias’ as a brotherhood in which society should live together. Deuteronomy actively counters this attitude. This paper studied the reason for mentioning ‘social trias’ introduced in the Old Testament and its meaning, focusing on the Covenant Law and Deuteronomy, using traditional historical methods. In traditional history, the concept of ‘social trias’ appears through the Khirbet Kayyapa pottery sculpture. This pottery fragment uses the style of school wisdom found in Northwest Semitic cultures. This concept appears very briefly in the covenant law of Exodus, and is generally introduced in Deuteronomy as a major member of Deuteronomic society. The concept of 'social trias' in Deuteronomy (Deuteronomy 10:18; 14:29; 16:11, 14; 24:17, 19, 20, 21; 26:12, 13; 27:19) appears in at least six texts. Each text is classified into a ritual text and a social regulation text according to the special literary techniques of Deuteronomy. Each text leads to understanding social trias within the framework of school wisdom. At least as a result, 'strangers, orphans, and widows' are recognized as the members who need the most protection in Deuteronomy society. The texts that mention the ‘Social Trias’ group in Deuteronomy borrow the style of the Northwest Semitic Treaty and devise and apply new internal and external sanctions mechanisms, and this concept emphasizes the new Deuteronomic community through school wisdom. This traditional historical criticism is very clearly revealed through the relics of Khirbet Qeiyafa. Deuteronomy's spirit of school wisdom became clearer at least through this pottery fragment, and it was confirmed that Deuteronomy's religious attitude was very similar to school wisdom. It is very encouraging that the texts that mention ‘Social Trias’ according to ‘Social Trias’ (Jeremiah, Ezekiel, and Psalms) that appear other than Deuteronomy mainly appear in texts from the exile or after the exile.