Chapter 5, Part 6C - Lieh Tzu

'These three precious heirlooms have been handed down for thirteen generations, but have never been in actual use. They lie stored away in a box, the seals of which have never been broken.'

'In spite of what you tell me,' said Lai Tan, 'I should like to borrow the third sword.'

K'ung Chou then returned his wife and children to him, and they fasted together for seven days. On the seventh day, in the dusk of evening, he knelt down and presented the third sword to Lai Tan, who received it with two low obeisances and went home again.
~ Lionel Giles translation via Terebess Asia Online ~

Go here to read the introductory post to the chapters of the Book of Lieh Tzu.