'Oath' in the Bible

Why have you not kept the oath of Yahweh and the command which I commanded you?"

Then he said, "Blessed be Yahweh the God of Israel who has promised with his mouth [to] David my father and fulfilled {by his oath}, saying,

[If] a man sins against his neighbor and he pronounces an oath against him to curse him, and the curse comes before your altar in this house,