Genesis 24:9
9 So the servant vput his hand under the thigh of Abraham his master and swore to him concerning this matter.
Genesis 47:29
29 And swhen the time drew near that Israel must die, he called his son Joseph and said to him, “If now tI have found favor in your sight, uput your hand under my thigh and vpromise to deal kindly and truly with me. wDo not bury me in Egypt,