Sheikh `Abd al-Hayy al-Farmâwî, dean of Qurânic Studies, Azhar University
The opinion that ghusl takes the place of wudû’ is the view held by the majority of the people of knowledge. They support their opinion with the following evidence:
1. Allah says: “Approach not the prayers…in a state of major ceremonial impurity except for one who is just passing (through the mosque) until after washing your whole body.” [Sûrah al-Nisâ’: 43]
This apparent meaning of this verse indicates that bathing is sufficient as purification for prayer, since neither wudû’ nor anything else is mentioned as a condition for purification.
2. Some people came to the Prophet (peace be upon him) and asked him about ghusl after sexual intercourse. They told him that they live in a cold place. The Prophet (peace be upon him) told them: “It would be enough for the one of you to pour water over his head three times.” In another narration he said: “For me, I pour water over my head thrice.” [Sâhîh Muslim (328)]
The obvious meaning of this hadîth is that performing ghusl in the manner described is sufficient to attain purification and no wudû’ is needed.
However, there are two conditions that should be observed so that the ghusl will be valid for purification. The first is that the intention for ghusl must be present. The second is that the person should rinse his mouth with water (madmadah) and clean out his nose by inhaling and exhaling water (istinshâq).
It is worth saying that, in any event, it is a Sunnah to perform wudû’ at the beginning of one’s ghusl.
And Allah knows best.
From the Fatwâ Department editors:
The view that madmadah and istinshâq are required for ghusl is the opinion of the Hanafî school of law. One of the opinions of the Hanbalî school of law is that these acts are obligatory for both wudû’ and ghusl.
In the Mâlikî and Shâfi`î schools of law, these acts are considered Sunnah for both wudû’ and ghusl.
Source: Islam Today