Thou shalt

1 Kings 2:8, 9, 37, 46
Keep an eye on Shimei the son of Gera, the Benjamite with you from Bahurim who called down bitter curses against me on the day I went to Mahanaim. But he came down to meet me at the Jordan, and I swore to him by the LORD: 'I will never kill you with the sword.' . . .

sware

1 Samuel 28:10
Then Saul swore to her by the LORD: "As surely as the LORD lives, no punishment shall come upon you for this."

1 Samuel 30:15
"Will you lead me to these raiders?" David asked. And the man replied, "Swear to me by God that you will not kill me or deliver me into the hands of my master, and I will lead you to them."

Hebrews 6:16
Men swear by someone greater than themselves, and their oath serves as a confirmation to end all argument.