The Bodhisatta was once a king. Some men were robbed in a forest and they chased after the thieves. They saw three men plowing a field and believed they were the robbers in disguise, so they took them to prison.
One day a country woman stood outside the palace crying out loudly that she needed her husband. The king brought her in to talk and she told him the story of the three men wrongly captured as thieves: they were her husband, son, and brother. The king agreed to let her choose one to go free and she chose her brother. Surprised by her answer, the king asked her why choose a brother, the least important of the three relations. She answered that she could find a new husband and have another son, but she could never get another brother. Impressed by her wisdom, the king let her take all three men back to the village.
In the Lifetime of the Buddha
Three men were mistaken for thieves, wrongly incarcerated, and then saved by a woman, just as had happened in the past. When the Buddha heard some of his disciples praising her, he told them this story so they knew that the same thing had happened to earlier births of these four people.