It would be foolish to refuse learning from your enemy.
That's what the Jedi did. Led by the exiles of Yoda and Obi-Wan Kenobi, the whole of the Order retreated from public life and began instead to support the rise of the Rebellion on countless worlds. As control within the Empire diminished to a tyrannical few, the leading figures across a broad spectrum of local governments learned a new kind of power, just as the Jedi themselves did. No longer dependent on the physical prowess of the Force, these Jedi exercised their mental abilities to astonishing effect, guiding the outcome of battles they could anticipate, in applying lessons learned during the Clone Wars.
As their Sith counterparts had done in the formative development of the Empire, these Jedi learned the art of social cunning, replacing manipulation with cooperation, a practice long forgotten in the moribund days of the Old Republic.
One by one, they faked their deaths. Since they had already been leading monastic lives, these were not difficult sacrifices for the Jedi to make, except the process of transforming themselves from figures of action to practitioners of the mind. New discipline was required. They would each have to depend primarily on themselves. There would no longer be a Council, but instead an expanded network of master and apprentice, again something borrowed from the Sith. In essence, each Jedi and their charge would operate independently and in their own way behave as if they were the last of their kind.
One by one, these efforts produced a new generation of heroes, many of whom had no idea the Jedi were responsible for their activities. The burgeoning expansion of Corellia into space led a freighter captain named Han Solo to Tatooine, for instance, after a brief romance with Aayla Secura sparked him onward.
As the Rebellion grew more successful and the career of Luke Skywalker began, some Jedi wondered if it was time to emerge from the shadows.
"Perhaps, in time," someone wise responded.