Final answer:
The Old Testament most strongly emphasizes the characteristic of God's expectation of obedience and exclusive worship by the Hebrews, a reflection of Yahweh's just and providential nature.
Step-by-step explanation:
The characteristic of God that the Old Testament stresses the most is His requirement for obedience, rooted in the covenantal relationship between Yahweh and the Hebrews. Yahweh, unlike the gods of surrounding polytheistic cultures, demanded exclusive worship and ethical living as part of the Covenant made with Abraham and later reaffirmed through Moses. This monotheistic deity was seen as just and righteous, punishing those deserving it rather than being capricious or cruel.
Throughout the history of the Hebrew people, the enforcement of Yahweh's judgment on individuals and the nation as a whole was a recurrent theme in the Old Testament, reinforcing the belief in His omnipotence and providence. Yahweh's centrality in Hebrew life is further underscored by the transformational shift to pure monotheism, a process that solidified under geopolitical pressures and the establishment of religious practices codified into law.
The Old Testament continually highlights the divine providence and moral expectations of Yahweh, positioning these as central to the Hebrew identity and community.