Talmud - Shabbat 33b
Rabbi Shimon bar Yoḥai and his son... They went and they hid in a cave. A miracle occurred and a carob tree was created for them as well as a spring of water. They would remove their clothes and sit covered in sand up to their necks. They would study Torah all day in that manner. At the time of prayer, they would dress, cover themselves, and pray, and they would again remove their clothes afterward so that they would not become tattered.
The Fiftieth Gate
There is a palace of hidden treasures.
In this palace there are forty-nine gates that separate good
from evil, the blessing from the curse.
Beyond them is a fiftieth gate larger than the entire world.
It is a hidden gate.
On this gate there is a lock, which has a narrow place
where a key may be inserted.
Come and see.
Through this gate all other gates may be seen.
Whoever enters the fiftieth gate sees through
God's eyes from one end of the world to the other.
The darkness or the light.
Come and see.
They key is the forgotten heart, the murdered prayer, the death
of memory.
It opens the blessing or the curse.
Come and see.
Of all the forms of wisdom, hindsight is by general consent the least merciful, the most unforgiving.
John Fletcher
Hindsight is of little value in the decision-making process. It distorts our memory for events that occurred at the time of the decision so that the actual consequence seems to have been a "foregone conclusion." Thus, it may be difficult to learn from our mistakes.
Diane F. Halpern
Talmud - Shabbat 33b (cont'd)
They sat in the cave for twelve years. Elijah the Prophet came and stood at the entrance to the cave and said: Who will inform bar Yoḥai that the emperor died and his decree has been abrogated?