Some people say that if blood flows from the wound then it does not break the Wudu. Please tell what is the strongest opinion with evidence from the Sunnah.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The most preponderant opinion of the Fuqaha (Islamic jurisprudents) is that the flow of blood from other than the male and female sexual organs does not break Wudu, whether by injury, or cupping or nose bleeding.  Anas (Radiya Allahu Anhu) narrated that "The Prophet (Sallallahu Alaihi wa Sallam) availed of cupping and prayed without making ablution.  He just washed the place of the cupping (from where the blood was flowing out)." [Reported by Daraqutni]

This is the opinion of Umar, Ibn Abbas, Ibn Abi Awfa, Jabir, Abu Hurairah, Ayisha, Saeed Bin Musaib (Radiya Allahu Anhum), and others.

Al-Baghawi said: ‘This is the opinion of most of the Sahaba (companions), and it is also the opinion of the Maliki and Shafi’e schools of thought.'

However, the Hanbali school of thought is of the view that the Wudu is null when much blood comes from the nose, because it is an impurity that comes out of the body.  This impurity is like that which flows out of the sexual organs.

Despite the fact that this opinion is not the most preponderant in terms of known evidence it is, however, more appropriate to make ablution to avoid the difference of opinion.