'Swore' in the Bible

Saul listened to the voice of Jonathan: and Saul swore, "As Yahweh lives, he shall not be put to death."

David swore moreover, and said, "Your father knows well that I have found favor in your eyes; and he says, 'Don't let Jonathan know this, lest he be grieved:' but truly as Yahweh lives, and as your soul lives, there is but a step between me and death."

David swore to Saul. Saul went home; but David and his men went up to the stronghold.

Saul swore to her by Yahweh, saying, "As Yahweh lives, no punishment shall happen to you for this thing."