'As the Lord Lives' in the Bible

And David answered Rechab and Baanah his brother, the sons of Rimmon of Beeroth, and said to them, As the Lord lives, who has redeemed my soul out of all adversity,

And David's anger was greatly kindled against the man. And he said to Nathan, As the Lord lives, the man who has done this shall surely die.

Then she said, Please let the king remember Jehovah your God, that you would not allow the avengers of blood to destroy any more, lest they should destroy my son. And he said, As the Lord lives, there shall not one hair of your son fall to the earth.

And Ittai answered the king and said, As the Lord lives, and as my lord the king lives, surely in whatever place my lord the king shall be, whether in death or life, even there also will your servant be.