Umar's ordering a Pregnant Woman to be stoned to death !!

A pregnant woman was brought before Umar Bin Khattab. On being questioned, she admitted that she was guilty of illicit sexual intercourse, and so the Caliph ordered her to be stoned.

Then Ali said: "Your order is applicable to this woman, but you have no authority over her child."

Umar acquitted the woman and said: "Women are incapable of giving birth to a man like Ali: If Ali had not been there, Umar would have been ruined."

He continued, saying: "May Allah not let me live so long as to face a difficult problem which Ali is not present to solve."

References:

Muhammad Bin Yusuf Ganji Shafi'i in his Kifayatu't-Talib Fi Manaqib-e-Amiru'l-Mu'minin Ali Bin Abi Talib;

Imam Ahmad Ibn Hanbal in his Musnad;

Bukhari in his Sahih;

Hamidi in Jam'-e-Bainu's-Sahihain;

Sheikh Sulayman Balkhi in Yanabiu'l-Mawadda, chapter IV, p.75, from Khawarizmi's Manaqib;

Imam Fakhru'd-din Razi in Arba'in, p.466;

Muhibu'd-din Tabari in Riyazu'n-Nazara, vol.II, p.196;

Khatib Khawarizmi in Manaqib, p.48;

Muhammad Bin Talha Shafi'i in Matalibu's-Su'ul, p.113;

and Imamu'l-Haram in Dhakha'iru'l-Uqba, p.80.