The Nachlas Avos tells that the Tana Yochai (Reb Shimon’s father) was married for many years, and didn’t have any children. Yochai told his wife that he wants to divorce and marry someone else, so he can keep the mitzvah of bearing children. His wife didn’t want a divorce and she cried and prayed intensely for children.
On the night of Rosh Hashanah, Yochai had a dream. He was in an orchard where there were many trees; some were tall, and some were small. He was leaning on a small tree, without fruit. An angel came into the orchard, carrying a barrel of water and started watering some of the trees.
Yochai understood that the trees represented people and whichever tree the angel watered, meant that this person would bear a child that year. How he hoped that the malach would pour some water on his sapling as well, so he would finally merit bearing a child. The malach came to Yochai’s tree. He didn’t pour water on it from the barrel. Instead, the angel took out a small jug of water, and poured the water over the tree. The tree immediately sprouted flowers, and beautiful fruit grew on this tree.
When he awoke, he told his wife about the dream. They understood that the dream was baring good tidings; telling them that they would have a child that year. On motzei Rosh Hashanah, Reb Yochai repeated his dream to his teacher, Reb Akiva. Reb Akiva agreed that the dream meant that they would have a child that year. Reb Yochai asked, “Why didn’t the angel water my tree from the barrel, as he watered all the other trees? What is the significance of that small jug filled with water?” Reb Akiva answered, “This jug wasn’t filled with water. It was filled with your wife’s tears; the tears she shed when she begged Hashem for children. In the merit of those tears you will bear a holy child.” That year, Reb Shimon bar Yochai was born.
This story, too, is a reminder not to lose hope. We should continue davening and trusting in Hashem, and in the end we will receive Hashem’s blessings.