Genesis 24:9

Therefore, the servant placed his hand under the thigh of Abraham, his lord, and he swore to him on his word

Other versions

King James Version

And the servant put his hand under the thigh of Abraham his master, and sware to him concerning that matter.

English Standard Version

So the servant put his hand under the thigh of Abraham his master and swore to him concerning this matter.

New International Version

So the servant put his hand under the thigh of his master Abraham and swore an oath to him concerning this matter.