Responsa על בבא בתרא 335:13

Q - A made an agreement to sell a parcel of land to B, before Hanukkah, and gave the latter a book as security, that the former would fulfill the agreement. A said to B, before an authoritative court, "If I do not carry out the terms of the agreement. This book shall be yours as of now." A failed to sell B the land before Hanukkah. Can A still sell the land to B, without incurring the penalty, although the designated time had elapsed?
A - In reality, both A and B were not sincerely interested about consummating the agreement before Hannukah. This deadline was intended to merely serve as a stimulus to complete the deal. The transaction can therefore be completed after the designated time had elapsed, and A need incur no penalty, whatsoever.