It rains when Heaven deems fit, mother remarries when she wants to--a popular saying often heard in China, what's the source of it?

It comes from a legend.

In ancient times there was a scholar called Zhu Yaozong who came first in the highest imperial examination. Conferred the title Number One Scholar, he was chosen to be the emperor's son-in-law. By convention, he would first return to his hometown in silken official robes. Before he left he begged the emperor for a favor--to erect a chastity archway in honor of his widowed mother. His request was granted.

His mother, however, appeared uneasy when she was told about the chastity archway. She had to admit that she was determined to remarry and her would-be husband was Zhu's former tutor to whom he owed a great deal. Devastated by the idea Zhu fell to his knees in front of his mother: “Mom. That's absolutely impossible. How could I face others if you do so. Besides, it will mean I have deceived the emperor--a felony deserving death penalty.”

As he was caught in a fix and nothing could be done, his mother sighed:“Since things have come to a head，let's trust to luck.” She then took off a skirt and handed it to him, saying:“Wash it tomorrow and dry it in the sun for a day. If it dries up by dawn the next morning, I'll drop the idea; if not, you are not to interfere, for it's the will of Heaven.”

That day was very fine with the sun shining brightly in a clear sky. But during the night clouds gathered and the sky became overcast. It broke into a violent shower towards daybreak. The skirt remained wet long after dawn. His mother said to him seriously:“Look here, son. It rains when Heaven deems fit, mother remarries when she wants to. The will of Heaven is not to be opposed.” So Zhu could do nothing but report to the emperor and express his readiness to be punished. The emperor was greatly surprised by the story and issued an imperial decree:“He who is unaware is not liable. Since the match has been made by Heaven, it has to be allowed.”

传说古时候有个名叫朱耀宗的书生，进京赶考高中状元。皇上殿试将他招为驸马。按惯例，朱耀宗一身锦绣新贵还乡。临行前，朱耀宗请求皇上为多年守寡一直不嫁的母亲竖立贞节牌坊?；噬献荚仕?。

当朱耀宗向娘述说了竖立贞节牌坊一事后，朱母露出了不安的神色，于是说出了想要嫁给朱耀宗的恩师张文举的想法。朱耀宗顿时跪在娘的面前：“娘，这千万使不得。您改嫁叫儿的脸往哪搁? 再说，欺君之罪难免杀身之祸啊。”

正值左右为难、无可奈何之际，朱母不由长叹一声：“听天由命吧。”她随手脱下身上一件罗裙，告诉朱耀宗说：“明天你替我把裙子洗干净，一天一夜晒干。如果裙子晒干，我答应不改嫁;如果裙子不干，天意如此，你也不用再阻拦了。”

这一天，晴空朗日，谁知当夜阴云密布，天明下起暴雨，裙子始终是湿漉漉的。朱耀宗心中叫苦不迭，知是天意。朱母则认认真真地对儿子说：“孩子，天要下雨，娘要嫁人，天意不可违!”朱耀宗只得将母亲和恩师的婚事报告皇上，请皇上治罪?；噬狭破?，降道御旨：“不知者不怪罪，天作之合，由他去吧。