Genesis 24:2

And Abraham said unto his eldest servant of his house, that ruled over all that he had, Put, I pray thee, thy hand under my thigh:

Geneva Bible - Therefore Abraham said unto his eldest servant of his house, which had the rule over all that he had. (*) (a) Put now thy hand under my thigh,
(*) Genesis 47:29 .
(a) Which ceremony declared, the servant’s obedience towards his master, and the master's power
over the servant.