'Swear by the Lord' in the Bible

that I may make thee swear by the LORD that is God of heaven and God of the earth, that thou shalt not take a wife unto my son, of the daughters of the Canaanites, among which I dwell.

Now therefore up and come out, and speak kindly unto thy servants, I swear by the LORD, except thou come out, there will not tarry one man with thee this night. And that will be worse unto thee, than all the evil that fell on thee from thine youth unto this hour."

In that day shall the five cities of Egypt speak with the Canaanites' tongue, and swear by the LORD of Hosts: the city of desolation shall be called one of them.

yea, and such as upon their house-tops worship and bow themselves unto the host of heaven: which swear by the LORD, and by their Milcom also: